664418881 has 12 divisors (see below), whose sum is σ = 773817408. Its totient is φ = 568822632.

The previous prime is 664418873. The next prime is 664418897. The reversal of 664418881 is 188814466.

It is not a de Polignac number, because 664418881 - 2³ = 664418873 is a prime.

It is a super-2 number, since 2×664418881² = 882904898858584322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (664418801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35820 + ... + 51106.

It is an arithmetic number, because the mean of its divisors is an integer number (64484784).

Almost surely, 2^664418881 is an apocalyptic number.

It is an amenable number.

664418881 is a deficient number, since it is larger than the sum of its proper divisors (109398527).

664418881 is a wasteful number, since it uses less digits than its factorization.

664418881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16188 (or 16181 counting only the distinct ones).

The product of its digits is 294912, while the sum is 46.

The square root of 664418881 is about 25776.3240397074. The cubic root of 664418881 is about 872.5975483909.

The spelling of 664418881 in words is "six hundred sixty-four million, four hundred eighteen thousand, eight hundred eighty-one".