256061381 has 2 divisors, whose sum is σ = 256061382. Its totient is φ = 256061380.

The previous prime is 256061353. The next prime is 256061401. The reversal of 256061381 is 183160652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157377025 + 98684356 = 12545^2 + 9934^2 .

It is a cyclic number.

It is not a de Polignac number, because 256061381 - 2⁶ = 256061317 is a prime.

It is a super-2 number, since 2×256061381² = 131134861679254322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256061321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128030690 + 128030691.

It is an arithmetic number, because the mean of its divisors is an integer number (128030691).

Almost surely, 2^256061381 is an apocalyptic number.

It is an amenable number.

256061381 is a deficient number, since it is larger than the sum of its proper divisors (1).

256061381 is an equidigital number, since it uses as much as digits as its factorization.

256061381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 256061381 is about 16001.9180412849. The cubic root of 256061381 is about 635.0111647860.

The spelling of 256061381 in words is "two hundred fifty-six million, sixty-one thousand, three hundred eighty-one".