1256131872 has 36 divisors (see below), whose sum is σ = 3572125830. Its totient is φ = 418710528.

The previous prime is 1256131859. The next prime is 1256131909. The reversal of 1256131872 is 2781316521.

1256131872 is a `hidden beast` number, since 1 + 25 + 613 + 18 + 7 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 813618576 + 442513296 = 28524^2 + 21036^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2180497 + ... + 2181072.

Almost surely, 2^1256131872 is an apocalyptic number.

1256131872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1256131872 is an abundant number, since it is smaller than the sum of its proper divisors (2315993958).

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

1256131872 is a wasteful number, since it uses less digits than its factorization.

1256131872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4361585 (or 4361574 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 1256131872 is about 35441.9507363802. The cubic root of 1256131872 is about 1078.9759016447.

The spelling of 1256131872 in words is "one billion, two hundred fifty-six million, one hundred thirty-one thousand, eight hundred seventy-two".