251564161 has 8 divisors (see below), whose sum is σ = 265075200. Its totient is φ = 238080240.

The previous prime is 251564149. The next prime is 251564177. The reversal of 251564161 is 161465152.

251564161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 251564161 - 2¹⁷ = 251433089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251564111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13920 + ... + 26398.

It is an arithmetic number, because the mean of its divisors is an integer number (33134400).

Almost surely, 2^251564161 is an apocalyptic number.

It is an amenable number.

251564161 is a deficient number, since it is larger than the sum of its proper divisors (13511039).

251564161 is a wasteful number, since it uses less digits than its factorization.

251564161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13559.

The product of its digits is 7200, while the sum is 31.

The square root of 251564161 is about 15860.7742875309. The cubic root of 251564161 is about 631.2716073250.

Subtracting from 251564161 its reverse (161465152), we obtain a palindrome (90099009).

The spelling of 251564161 in words is "two hundred fifty-one million, five hundred sixty-four thousand, one hundred sixty-one".