1243981440 has 384 divisors, whose sum is σ = 4761666000. Its totient is φ = 297271296.

The previous prime is 1243981439. The next prime is 1243981441. The reversal of 1243981440 is 441893421.

It is a happy number.

1243981440 is a `hidden beast` number, since 124 + 3 + 98 + 1 + 440 = 666.

It is an interprime number because it is at equal distance from previous prime (1243981439) and next prime (1243981441).

It can be written as a sum of positive squares in 8 ways, for example, as 643535424 + 600446016 = 25368^2 + 24504^2 .

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1243981395 and 1243981404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243981441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2770336 + ... + 2770784.

Almost surely, 2^1243981440 is an apocalyptic number.

1243981440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1243981440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2380833000).

1243981440 is an abundant number, since it is smaller than the sum of its proper divisors (3517684560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1243981440 is a wasteful number, since it uses less digits than its factorization.

1243981440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 1243981440 is about 35270.1210658540. The cubic root of 1243981440 is about 1075.4856835464.

It can be divided in two parts, 1243981 and 440, that added together give a palindrome (1244421).

The spelling of 1243981440 in words is "one billion, two hundred forty-three million, nine hundred eighty-one thousand, four hundred forty".