17981668 has 6 divisors (see below), whose sum is σ = 31467926. Its totient is φ = 8990832.

The previous prime is 17981651. The next prime is 17981687. The reversal of 17981668 is 86618971.

It can be written as a sum of positive squares in only one way, i.e., 14379264 + 3602404 = 3792^2 + 1898^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2247705 + ... + 2247712.

Almost surely, 2^17981668 is an apocalyptic number.

It is an amenable number.

17981668 is a deficient number, since it is larger than the sum of its proper divisors (13486258).

17981668 is a wasteful number, since it uses less digits than its factorization.

17981668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4495421 (or 4495419 counting only the distinct ones).

The product of its digits is 145152, while the sum is 46.

The square root of 17981668 is about 4240.4796898464. The cubic root of 17981668 is about 261.9851398832.

The spelling of 17981668 in words is "seventeen million, nine hundred eighty-one thousand, six hundred sixty-eight".