251423601521 has 2 divisors, whose sum is σ = 251423601522. Its totient is φ = 251423601520.

The previous prime is 251423601511. The next prime is 251423601581. The reversal of 251423601521 is 125106324152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 215309920225 + 36113681296 = 464015^2 + 190036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251423601521 is a prime.

It is not a weakly prime, because it can be changed into another prime (251423601511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125711800760 + 125711800761.

It is an arithmetic number, because the mean of its divisors is an integer number (125711800761).

Almost surely, 2^251423601521 is an apocalyptic number.

It is an amenable number.

251423601521 is a deficient number, since it is larger than the sum of its proper divisors (1).

251423601521 is an equidigital number, since it uses as much as digits as its factorization.

251423601521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 251423601521 its reverse (125106324152), we get a palindrome (376529925673).

The spelling of 251423601521 in words is "two hundred fifty-one billion, four hundred twenty-three million, six hundred one thousand, five hundred twenty-one".