257981623 has 2 divisors, whose sum is σ = 257981624. Its totient is φ = 257981622.

The previous prime is 257981611. The next prime is 257981629. The reversal of 257981623 is 326189752.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257981623 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 257981623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257981629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128990811 + 128990812.

It is an arithmetic number, because the mean of its divisors is an integer number (128990812).

Almost surely, 2^257981623 is an apocalyptic number.

257981623 is a deficient number, since it is larger than the sum of its proper divisors (1).

257981623 is an equidigital number, since it uses as much as digits as its factorization.

257981623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 43.

The square root of 257981623 is about 16061.8063429989. The cubic root of 257981623 is about 636.5945607267.

The spelling of 257981623 in words is "two hundred fifty-seven million, nine hundred eighty-one thousand, six hundred twenty-three".