256136261 has 2 divisors, whose sum is σ = 256136262. Its totient is φ = 256136260.

The previous prime is 256136219. The next prime is 256136327. The reversal of 256136261 is 162631652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221444161 + 34692100 = 14881^2 + 5890^2 .

It is a cyclic number.

It is not a de Polignac number, because 256136261 - 2⁶ = 256136197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256136561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128068130 + 128068131.

It is an arithmetic number, because the mean of its divisors is an integer number (128068131).

Almost surely, 2^256136261 is an apocalyptic number.

It is an amenable number.

256136261 is a deficient number, since it is larger than the sum of its proper divisors (1).

256136261 is an equidigital number, since it uses as much as digits as its factorization.

256136261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 32.

The square root of 256136261 is about 16004.2575897790. The cubic root of 256136261 is about 635.0730575005.

The spelling of 256136261 in words is "two hundred fifty-six million, one hundred thirty-six thousand, two hundred sixty-one".