251110561 has 4 divisors (see below), whose sum is σ = 270426772. Its totient is φ = 231794352.

The previous prime is 251110547. The next prime is 251110577. The reversal of 251110561 is 165011152.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45360225 + 205750336 = 6735^2 + 14344^2 .

It is a cyclic number.

It is not a de Polignac number, because 251110561 - 2⁵ = 251110529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251110591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9658086 + ... + 9658111.

It is an arithmetic number, because the mean of its divisors is an integer number (67606693).

Almost surely, 2^251110561 is an apocalyptic number.

It is an amenable number.

251110561 is a deficient number, since it is larger than the sum of its proper divisors (19316211).

251110561 is a wasteful number, since it uses less digits than its factorization.

251110561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19316210.

The product of its (nonzero) digits is 300, while the sum is 22.

The square root of 251110561 is about 15846.4684078188. The cubic root of 251110561 is about 630.8919598729.

The spelling of 251110561 in words is "two hundred fifty-one million, one hundred ten thousand, five hundred sixty-one".