668388186 has 20 divisors (see below), whose sum is σ = 1497685002. Its totient is φ = 222796008.

The previous prime is 668388121. The next prime is 668388197. The reversal of 668388186 is 681883866.

It can be written as a sum of positive squares in only one way, i.e., 500193225 + 168194961 = 22365^2 + 12969^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2062765 + ... + 2063088.

Almost surely, 2^668388186 is an apocalyptic number.

668388186 is an abundant number, since it is smaller than the sum of its proper divisors (829296816).

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

668388186 is a wasteful number, since it uses less digits than its factorization.

668388186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4125867 (or 4125858 counting only the distinct ones).

The product of its digits is 2654208, while the sum is 54.

The square root of 668388186 is about 25853.2045595899. The cubic root of 668388186 is about 874.3317612508.

The spelling of 668388186 in words is "six hundred sixty-eight million, three hundred eighty-eight thousand, one hundred eighty-six".