1256115816 has 64 divisors (see below), whose sum is σ = 3510715200. Its totient is φ = 416124864.

The previous prime is 1256115793. The next prime is 1256115827. The reversal of 1256115816 is 6185116521.

1256115816 is a `hidden beast` number, since 1 + 2 + 561 + 15 + 81 + 6 = 666.

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

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 15 ways as a sum of consecutive naturals, for example, 17370 + ... + 53046.

It is an arithmetic number, because the mean of its divisors is an integer number (54854925).

Almost surely, 2^1256115816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1256115816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1755357600).

1256115816 is an abundant number, since it is smaller than the sum of its proper divisors (2254599384).

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

1256115816 is a wasteful number, since it uses less digits than its factorization.

1256115816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35855 (or 35845 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The square root of 1256115816 is about 35441.7242244223. The cubic root of 1256115816 is about 1078.9713044334.

The spelling of 1256115816 in words is "one billion, two hundred fifty-six million, one hundred fifteen thousand, eight hundred sixteen".