257198987 has 2 divisors, whose sum is σ = 257198988. Its totient is φ = 257198986.

The previous prime is 257198959. The next prime is 257199013. The reversal of 257198987 is 789891752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 257198987 - 2⁶ = 257198923 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (257198917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128599493 + 128599494.

It is an arithmetic number, because the mean of its divisors is an integer number (128599494).

Almost surely, 2^257198987 is an apocalyptic number.

257198987 is a deficient number, since it is larger than the sum of its proper divisors (1).

257198987 is an equidigital number, since it uses as much as digits as its factorization.

257198987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 56.

The square root of 257198987 is about 16037.4245750370. The cubic root of 257198987 is about 635.9501653594.

The spelling of 257198987 in words is "two hundred fifty-seven million, one hundred ninety-eight thousand, nine hundred eighty-seven".