668581418 has 8 divisors (see below), whose sum is σ = 1012801860. Its totient is φ = 330980800.

The previous prime is 668581391. The next prime is 668581427. The reversal of 668581418 is 814185866.

It can be written as a sum of positive squares in 2 ways, for example, as 599907049 + 68674369 = 24493^2 + 8287^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×668581418² = 894002224989781448, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1654703 + ... + 1655106.

Almost surely, 2^668581418 is an apocalyptic number.

668581418 is a deficient number, since it is larger than the sum of its proper divisors (344220442).

668581418 is a wasteful number, since it uses less digits than its factorization.

668581418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3309912.

The product of its digits is 368640, while the sum is 47.

The square root of 668581418 is about 25856.9413891125. The cubic root of 668581418 is about 874.4160099952.

The spelling of 668581418 in words is "six hundred sixty-eight million, five hundred eighty-one thousand, four hundred eighteen".