256420765 has 16 divisors (see below), whose sum is σ = 316892016. Its totient is φ = 199065600.

The previous prime is 256420763. The next prime is 256420771. The reversal of 256420765 is 567024652.

It can be written as a sum of positive squares in 8 ways, for example, as 10903204 + 245517561 = 3302^2 + 15669^2 .

It is not a de Polignac number, because 256420765 - 2¹ = 256420763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256420763) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36325 + ... + 42805.

It is an arithmetic number, because the mean of its divisors is an integer number (19805751).

Almost surely, 2^256420765 is an apocalyptic number.

It is an amenable number.

256420765 is a deficient number, since it is larger than the sum of its proper divisors (60471251).

256420765 is a wasteful number, since it uses less digits than its factorization.

256420765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6720.

The product of its (nonzero) digits is 100800, while the sum is 37.

The square root of 256420765 is about 16013.1435077564. The cubic root of 256420765 is about 635.3081068299.

The spelling of 256420765 in words is "two hundred fifty-six million, four hundred twenty thousand, seven hundred sixty-five".