668521384 has 32 divisors (see below), whose sum is σ = 1336176000. Its totient is φ = 312653952.

The previous prime is 668521361. The next prime is 668521393. The reversal of 668521384 is 483125866.

It is a self number, because there is not a number n which added to its sum of digits gives 668521384.

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, 15829 + ... + 39844.

It is an arithmetic number, because the mean of its divisors is an integer number (41755500).

Almost surely, 2^668521384 is an apocalyptic number.

It is an amenable number.

668521384 is a deficient number, since it is larger than the sum of its proper divisors (667654616).

668521384 is a wasteful number, since it uses less digits than its factorization.

668521384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55777 (or 55773 counting only the distinct ones).

The product of its digits is 276480, while the sum is 43.

The square root of 668521384 is about 25855.7804755532. The cubic root of 668521384 is about 874.3898370363.

The spelling of 668521384 in words is "six hundred sixty-eight million, five hundred twenty-one thousand, three hundred eighty-four".