1256427440 has 160 divisors (see below), whose sum is σ = 3254791680. Its totient is φ = 448892928.

The previous prime is 1256427439. The next prime is 1256427443. The reversal of 1256427440 is 447246521.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1256427440.

It is not an unprimeable number, because it can be changed into a prime (1256427443) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2901464 + ... + 2901896.

It is an arithmetic number, because the mean of its divisors is an integer number (20342448).

Almost surely, 2^1256427440 is an apocalyptic number.

1256427440 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 1256427440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1627395840).

1256427440 is an abundant number, since it is smaller than the sum of its proper divisors (1998364240).

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

1256427440 is a wasteful number, since it uses less digits than its factorization.

1256427440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 571 (or 565 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 35.

The square root of 1256427440 is about 35446.1202390332. The cubic root of 1256427440 is about 1079.0605227333.

It can be divided in two parts, 12564 and 27440, that added together give a palindrome (40004).

The spelling of 1256427440 in words is "one billion, two hundred fifty-six million, four hundred twenty-seven thousand, four hundred forty".