1256056815 has 32 divisors (see below), whose sum is σ = 2291599296. Its totient is φ = 581990400.

The previous prime is 1256056759. The next prime is 1256056817. The reversal of 1256056815 is 5186506521.

It is not a de Polignac number, because 1256056815 - 2⁷ = 1256056687 is a prime.

It is a super-3 number, since 3×1256056815³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256056817) 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, 186136 + ... + 192765.

It is an arithmetic number, because the mean of its divisors is an integer number (71612478).

Almost surely, 2^1256056815 is an apocalyptic number.

1256056815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1256056815 is a deficient number, since it is larger than the sum of its proper divisors (1035542481).

1256056815 is a wasteful number, since it uses less digits than its factorization.

1256056815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378939.

The product of its (nonzero) digits is 72000, while the sum is 39.

The square root of 1256056815 is about 35440.8918482591. The cubic root of 1256056815 is about 1078.9544107198.

It can be divided in two parts, 125 and 6056815, that added together give a triangular number (6056940 = T₃₄₈₀).

The spelling of 1256056815 in words is "one billion, two hundred fifty-six million, fifty-six thousand, eight hundred fifteen".