256521236 has 6 divisors (see below), whose sum is σ = 448912170. Its totient is φ = 128260616.

The previous prime is 256521227. The next prime is 256521263. The reversal of 256521236 is 632125652.

It can be written as a sum of positive squares in only one way, i.e., 150307600 + 106213636 = 12260^2 + 10306^2 .

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32065151 + ... + 32065158.

It is an arithmetic number, because the mean of its divisors is an integer number (74818695).

Almost surely, 2^256521236 is an apocalyptic number.

It is an amenable number.

256521236 is a deficient number, since it is larger than the sum of its proper divisors (192390934).

256521236 is a wasteful number, since it uses less digits than its factorization.

256521236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64130313 (or 64130311 counting only the distinct ones).

The product of its digits is 21600, while the sum is 32.

The square root of 256521236 is about 16016.2803422018. The cubic root of 256521236 is about 635.3910716475.

Adding to 256521236 its reverse (632125652), we get a palindrome (888646888).

The spelling of 256521236 in words is "two hundred fifty-six million, five hundred twenty-one thousand, two hundred thirty-six".