256207261 has 4 divisors (see below), whose sum is σ = 257326300. Its totient is φ = 255088224.

The previous prime is 256207253. The next prime is 256207279. The reversal of 256207261 is 162702652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 243204025 + 13003236 = 15595^2 + 3606^2 .

It is a cyclic number.

It is not a de Polignac number, because 256207261 - 2³ = 256207253 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 (256207961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 559176 + ... + 559633.

It is an arithmetic number, because the mean of its divisors is an integer number (64331575).

Almost surely, 2^256207261 is an apocalyptic number.

It is an amenable number.

256207261 is a deficient number, since it is larger than the sum of its proper divisors (1119039).

256207261 is a wasteful number, since it uses less digits than its factorization.

256207261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1119038.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 256207261 is about 16006.4755958331. The cubic root of 256207261 is about 635.1317320269.

The spelling of 256207261 in words is "two hundred fifty-six million, two hundred seven thousand, two hundred sixty-one".