1251822781440 has 2112 divisors, whose sum is σ = 5716707010560. Its totient is φ = 255122472960.

The previous prime is 1251822781421. The next prime is 1251822781453. The reversal of 1251822781440 is 441872281521.

1251822781440 is a `hidden beast` number, since 1 + 2 + 5 + 182 + 27 + 8 + 1 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (2112).

It is a super-2 number, since 2×1251822781440² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 6993423271 + ... + 6993423449.

Almost surely, 2^{1251822781440} is an apocalyptic number.

1251822781440 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 1251822781440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2858353505280).

1251822781440 is an abundant number, since it is smaller than the sum of its proper divisors (4464884229120).

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

1251822781440 is a wasteful number, since it uses less digits than its factorization.

1251822781440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 286720, while the sum is 45.

The spelling of 1251822781440 in words is "one trillion, two hundred fifty-one billion, eight hundred twenty-two million, seven hundred eighty-one thousand, four hundred forty".