251320401 has 40 divisors (see below), whose sum is σ = 399750120. Its totient is φ = 156805632.

The previous prime is 251320397. The next prime is 251320403. The reversal of 251320401 is 104023152.

It can be written as a sum of positive squares in 4 ways, for example, as 127577025 + 123743376 = 11295^2 + 11124^2 .

It is not a de Polignac number, because 251320401 - 2² = 251320397 is a prime.

It is not an unprimeable number, because it can be changed into a prime (251320403) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 314935 + ... + 315731.

It is an arithmetic number, because the mean of its divisors is an integer number (9993753).

Almost surely, 2^251320401 is an apocalyptic number.

It is an amenable number.

251320401 is a deficient number, since it is larger than the sum of its proper divisors (148429719).

251320401 is a wasteful number, since it uses less digits than its factorization.

251320401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055 (or 1046 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 251320401 is about 15853.0880587979. The cubic root of 251320401 is about 631.0676454479.

Adding to 251320401 its reverse (104023152), we get a palindrome (355343553).

The spelling of 251320401 in words is "two hundred fifty-one million, three hundred twenty thousand, four hundred one".