664720131 has 4 divisors (see below), whose sum is σ = 886293512. Its totient is φ = 443146752.

The previous prime is 664720123. The next prime is 664720151. The reversal of 664720131 is 131027466.

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

It is not a de Polignac number, because 664720131 - 2³ = 664720123 is a prime.

It is a super-2 number, since 2×664720131² = 883705705113314322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664720151) 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, 110786686 + ... + 110786691.

It is an arithmetic number, because the mean of its divisors is an integer number (221573378).

Almost surely, 2^664720131 is an apocalyptic number.

664720131 is a deficient number, since it is larger than the sum of its proper divisors (221573381).

664720131 is a wasteful number, since it uses less digits than its factorization.

664720131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221573380.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 664720131 is about 25782.1669182402. The cubic root of 664720131 is about 872.7294081259.

Adding to 664720131 its reverse (131027466), we get a palindrome (795747597).

The spelling of 664720131 in words is "six hundred sixty-four million, seven hundred twenty thousand, one hundred thirty-one".