257402381 has 2 divisors, whose sum is σ = 257402382. Its totient is φ = 257402380.

The previous prime is 257402357. The next prime is 257402399. The reversal of 257402381 is 183204752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 239475625 + 17926756 = 15475^2 + 4234^2 .

It is a cyclic number.

It is not a de Polignac number, because 257402381 - 2²⁶ = 190293517 is a prime.

It is a super-2 number, since 2×257402381² = 132511971488938322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257402351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128701190 + 128701191.

It is an arithmetic number, because the mean of its divisors is an integer number (128701191).

Almost surely, 2^257402381 is an apocalyptic number.

It is an amenable number.

257402381 is a deficient number, since it is larger than the sum of its proper divisors (1).

257402381 is an equidigital number, since it uses as much as digits as its factorization.

257402381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 32.

The square root of 257402381 is about 16043.7645519996. The cubic root of 257402381 is about 636.1177585110.

The spelling of 257402381 in words is "two hundred fifty-seven million, four hundred two thousand, three hundred eighty-one".