665953864 has 8 divisors (see below), whose sum is σ = 1248663510. Its totient is φ = 332976928.

The previous prime is 665953859. The next prime is 665953877. The reversal of 665953864 is 468359566.

It can be written as a sum of positive squares in only one way, i.e., 573985764 + 91968100 = 23958^2 + 9590^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41622109 + ... + 41622124.

Almost surely, 2^665953864 is an apocalyptic number.

It is an amenable number.

665953864 is a deficient number, since it is larger than the sum of its proper divisors (582709646).

665953864 is a wasteful number, since it uses less digits than its factorization.

665953864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83244239 (or 83244235 counting only the distinct ones).

The product of its digits is 4665600, while the sum is 52.

The square root of 665953864 is about 25806.0819188036. The cubic root of 665953864 is about 873.2690084641.

It can be divided in two parts, 665 and 953864, that added together give a square (954529 = 977²).

The spelling of 665953864 in words is "six hundred sixty-five million, nine hundred fifty-three thousand, eight hundred sixty-four".