256504391 has 24 divisors (see below), whose sum is σ = 314156640. Its totient is φ = 207789120.

The previous prime is 256504373. The next prime is 256504393. The reversal of 256504391 is 193405652.

It is not a de Polignac number, because 256504391 - 2¹⁰ = 256503367 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256504393) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42806 + ... + 48428.

It is an arithmetic number, because the mean of its divisors is an integer number (13089860).

Almost surely, 2^256504391 is an apocalyptic number.

256504391 is a deficient number, since it is larger than the sum of its proper divisors (57652249).

256504391 is a wasteful number, since it uses less digits than its factorization.

256504391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5687 (or 5676 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 35.

The square root of 256504391 is about 16015.7544624036. The cubic root of 256504391 is about 635.3771632513.

The spelling of 256504391 in words is "two hundred fifty-six million, five hundred four thousand, three hundred ninety-one".