666491520 has 64 divisors (see below), whose sum is σ = 2124447840. Its totient is φ = 177730560.

The previous prime is 666491513. The next prime is 666491521. The reversal of 666491520 is 25194666.

666491520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (666491521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171646 + ... + 175485.

Almost surely, 2^666491520 is an apocalyptic number.

666491520 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

666491520 is an abundant number, since it is smaller than the sum of its proper divisors (1457956320).

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

666491520 is a wasteful number, since it uses less digits than its factorization.

666491520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347153 (or 347141 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 666491520 is about 25816.4970513042. The cubic root of 666491520 is about 873.5039556825.

The spelling of 666491520 in words is "six hundred sixty-six million, four hundred ninety-one thousand, five hundred twenty".