666664320 has 128 divisors (see below), whose sum is σ = 2428611840. Its totient is φ = 152377344.

The previous prime is 666664301. The next prime is 666664321. The reversal of 666664320 is 23466666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×666664320² = 888882631122124800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666664321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11362 + ... + 38241.

It is an arithmetic number, because the mean of its divisors is an integer number (18973530).

Almost surely, 2^666664320 is an apocalyptic number.

666664320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666664320 is an abundant number, since it is smaller than the sum of its proper divisors (1761947520).

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

666664320 is a wasteful number, since it uses less digits than its factorization.

666664320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49632 (or 49620 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 39.

The square root of 666664320 is about 25819.8435316715. The cubic root of 666664320 is about 873.5794397340.

The spelling of 666664320 in words is "six hundred sixty-six million, six hundred sixty-four thousand, three hundred twenty".