668386978 has 32 divisors (see below), whose sum is σ = 1222669440. Its totient is φ = 267649920.

The previous prime is 668386937. The next prime is 668387003. The reversal of 668386978 is 879683866.

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, 2208 + ... + 36628.

It is an arithmetic number, because the mean of its divisors is an integer number (38208420).

Almost surely, 2^668386978 is an apocalyptic number.

668386978 is a deficient number, since it is larger than the sum of its proper divisors (554282462).

668386978 is a wasteful number, since it uses less digits than its factorization.

668386978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34522.

The product of its digits is 20901888, while the sum is 61.

The square root of 668386978 is about 25853.1811969050. The cubic root of 668386978 is about 874.3312345143.

The spelling of 668386978 in words is "six hundred sixty-eight million, three hundred eighty-six thousand, nine hundred seventy-eight".