257157409 has 2 divisors, whose sum is σ = 257157410. Its totient is φ = 257157408.

The previous prime is 257157389. The next prime is 257157427. The reversal of 257157409 is 904751752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208715809 + 48441600 = 14447^2 + 6960^2 .

It is a cyclic number.

It is not a de Polignac number, because 257157409 - 2⁹ = 257156897 is a prime.

It is a super-2 number, since 2×257157409² = 132259866007186562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (257157449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128578704 + 128578705.

It is an arithmetic number, because the mean of its divisors is an integer number (128578705).

Almost surely, 2^257157409 is an apocalyptic number.

It is an amenable number.

257157409 is a deficient number, since it is larger than the sum of its proper divisors (1).

257157409 is an equidigital number, since it uses as much as digits as its factorization.

257157409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88200, while the sum is 40.

The square root of 257157409 is about 16036.1282421911. The cubic root of 257157409 is about 635.9158949277.

It can be divided in two parts, 25715 and 7409, that added together give a square (33124 = 182²).

The spelling of 257157409 in words is "two hundred fifty-seven million, one hundred fifty-seven thousand, four hundred nine".