668493952 has 128 divisors (see below), whose sum is σ = 1573084800. Its totient is φ = 277094400.

The previous prime is 668493899. The next prime is 668493977. The reversal of 668493952 is 259394866.

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

It is a self number, because there is not a number n which added to its sum of digits gives 668493952.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6618702 + ... + 6618802.

It is an arithmetic number, because the mean of its divisors is an integer number (12289725).

Almost surely, 2^668493952 is an apocalyptic number.

668493952 is the 12928-th decagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668493952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786542400).

668493952 is an abundant number, since it is smaller than the sum of its proper divisors (904590848).

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

668493952 is a wasteful number, since it uses less digits than its factorization.

668493952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294 (or 282 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 52.

The square root of 668493952 is about 25855.2499891221. The cubic root of 668493952 is about 874.3778770149.

The spelling of 668493952 in words is "six hundred sixty-eight million, four hundred ninety-three thousand, nine hundred fifty-two".