257969891 has 4 divisors (see below), whose sum is σ = 258025512. Its totient is φ = 257914272.

The previous prime is 257969867. The next prime is 257969939. The reversal of 257969891 is 198969752.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257969891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257969801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20150 + ... + 30363.

It is an arithmetic number, because the mean of its divisors is an integer number (64506378).

Almost surely, 2^257969891 is an apocalyptic number.

257969891 is a deficient number, since it is larger than the sum of its proper divisors (55621).

257969891 is an equidigital number, since it uses as much as digits as its factorization.

257969891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55620.

The product of its digits is 2449440, while the sum is 56.

The square root of 257969891 is about 16061.4411246314. The cubic root of 257969891 is about 636.5849106329.

The spelling of 257969891 in words is "two hundred fifty-seven million, nine hundred sixty-nine thousand, eight hundred ninety-one".