664466640 has 40 divisors (see below), whose sum is σ = 2059847328. Its totient is φ = 177191040.

The previous prime is 664466639. The next prime is 664466681. The reversal of 664466640 is 46664466.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 664466592 and 664466601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1384066 + ... + 1384545.

Almost surely, 2^664466640 is an apocalyptic number.

664466640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

664466640 is an abundant number, since it is smaller than the sum of its proper divisors (1395380688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664466640 is a wasteful number, since it uses less digits than its factorization.

664466640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2768627 (or 2768621 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 42.

The square root of 664466640 is about 25777.2504352190. The cubic root of 664466640 is about 872.6184555771.

The spelling of 664466640 in words is "six hundred sixty-four million, four hundred sixty-six thousand, six hundred forty".