666391424 has 32 divisors (see below), whose sum is σ = 1330989840. Its totient is φ = 332339200.

The previous prime is 666391393. The next prime is 666391457. The reversal of 666391424 is 424193666.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44837 + ... + 57819.

Almost surely, 2^666391424 is an apocalyptic number.

666391424 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

666391424 is a deficient number, since it is larger than the sum of its proper divisors (664598416).

666391424 is a wasteful number, since it uses less digits than its factorization.

666391424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13398 (or 13386 counting only the distinct ones).

The product of its digits is 186624, while the sum is 41.

The square root of 666391424 is about 25814.5583731351. The cubic root of 666391424 is about 873.4602248789.

The spelling of 666391424 in words is "six hundred sixty-six million, three hundred ninety-one thousand, four hundred twenty-four".