251255421 has 24 divisors (see below), whose sum is σ = 374230584. Its totient is φ = 162339840.

The previous prime is 251255399. The next prime is 251255437. The reversal of 251255421 is 124552152.

It can be written as a sum of positive squares in 4 ways, for example, as 27154521 + 224100900 = 5211^2 + 14970^2 .

It is not a de Polignac number, because 251255421 - 2⁹ = 251254909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251255441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55765 + ... + 60101.

It is an arithmetic number, because the mean of its divisors is an integer number (15592941).

Almost surely, 2^251255421 is an apocalyptic number.

It is an amenable number.

251255421 is a deficient number, since it is larger than the sum of its proper divisors (122975163).

251255421 is a wasteful number, since it uses less digits than its factorization.

251255421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4541 (or 4538 counting only the distinct ones).

The product of its digits is 4000, while the sum is 27.

The square root of 251255421 is about 15851.0384833297. The cubic root of 251255421 is about 631.0132523171.

The spelling of 251255421 in words is "two hundred fifty-one million, two hundred fifty-five thousand, four hundred twenty-one".