257443661 has 2 divisors, whose sum is σ = 257443662. Its totient is φ = 257443660.

The previous prime is 257443649. The next prime is 257443717. The reversal of 257443661 is 166344752.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190302025 + 67141636 = 13795^2 + 8194^2 .

It is a cyclic number.

It is not a de Polignac number, because 257443661 - 2²⁶ = 190334797 is a prime.

It is a Chen prime.

It is equal to p_14063969 and since 257443661 and 14063969 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257443621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128721830 + 128721831.

It is an arithmetic number, because the mean of its divisors is an integer number (128721831).

Almost surely, 2^257443661 is an apocalyptic number.

It is an amenable number.

257443661 is a deficient number, since it is larger than the sum of its proper divisors (1).

257443661 is an equidigital number, since it uses as much as digits as its factorization.

257443661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 38.

The square root of 257443661 is about 16045.0509815332. The cubic root of 257443661 is about 636.1517617415.

The spelling of 257443661 in words is "two hundred fifty-seven million, four hundred forty-three thousand, six hundred sixty-one".