665390624 has 12 divisors (see below), whose sum is σ = 1309987854. Its totient is φ = 332695296.

The previous prime is 665390617. The next prime is 665390639. The reversal of 665390624 is 426093566.

It can be written as a sum of positive squares in only one way, i.e., 542890000 + 122500624 = 23300^2 + 11068^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10396697 + ... + 10396760.

Almost surely, 2^665390624 is an apocalyptic number.

It is an amenable number.

665390624 is a deficient number, since it is larger than the sum of its proper divisors (644597230).

665390624 is a wasteful number, since it uses less digits than its factorization.

665390624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20793467 (or 20793459 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 41.

The square root of 665390624 is about 25795.1666790506. The cubic root of 665390624 is about 873.0227457753.

The spelling of 665390624 in words is "six hundred sixty-five million, three hundred ninety thousand, six hundred twenty-four".