257669021 has 2 divisors, whose sum is σ = 257669022. Its totient is φ = 257669020.

The previous prime is 257668997. The next prime is 257669039. The reversal of 257669021 is 120966752.

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., 251222500 + 6446521 = 15850^2 + 2539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257669021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257669081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128834510 + 128834511.

It is an arithmetic number, because the mean of its divisors is an integer number (128834511).

Almost surely, 2^257669021 is an apocalyptic number.

It is an amenable number.

257669021 is a deficient number, since it is larger than the sum of its proper divisors (1).

257669021 is an equidigital number, since it uses as much as digits as its factorization.

257669021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 257669021 is about 16052.0721715298. The cubic root of 257669021 is about 636.3373315973.

The spelling of 257669021 in words is "two hundred fifty-seven million, six hundred sixty-nine thousand, twenty-one".