251983891 has 2 divisors, whose sum is σ = 251983892. Its totient is φ = 251983890.

The previous prime is 251983861. The next prime is 251983937. The reversal of 251983891 is 198389152.

It is an a-pointer prime, because the next prime (251983937) can be obtained adding 251983891 to its sum of digits (46).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 251983891 - 2⁹ = 251983379 is a prime.

It is not a weakly prime, because it can be changed into another prime (251983811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125991945 + 125991946.

It is an arithmetic number, because the mean of its divisors is an integer number (125991946).

Almost surely, 2^251983891 is an apocalyptic number.

251983891 is a deficient number, since it is larger than the sum of its proper divisors (1).

251983891 is an equidigital number, since it uses as much as digits as its factorization.

251983891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 46.

The square root of 251983891 is about 15874.0004724707. Note that the first 3 decimals coincide. The cubic root of 251983891 is about 631.6225004528.

The spelling of 251983891 in words is "two hundred fifty-one million, nine hundred eighty-three thousand, eight hundred ninety-one".