251541989 has 2 divisors, whose sum is σ = 251541990. Its totient is φ = 251541988.

The previous prime is 251541977. The next prime is 251542009. The reversal of 251541989 is 989145152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207849889 + 43692100 = 14417^2 + 6610^2 .

It is a cyclic number.

It is not a de Polignac number, because 251541989 - 2⁴ = 251541973 is a prime.

It is a super-2 number, since 2×251541989² = 126546744460152242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251541089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125770994 + 125770995.

It is an arithmetic number, because the mean of its divisors is an integer number (125770995).

Almost surely, 2^251541989 is an apocalyptic number.

It is an amenable number.

251541989 is a deficient number, since it is larger than the sum of its proper divisors (1).

251541989 is an equidigital number, since it uses as much as digits as its factorization.

251541989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 44.

The square root of 251541989 is about 15860.0753150797. The cubic root of 251541989 is about 631.2530607439.

The spelling of 251541989 in words is "two hundred fifty-one million, five hundred forty-one thousand, nine hundred eighty-nine".