20918668 has 12 divisors (see below), whose sum is σ = 36673560. Its totient is φ = 10440512.

The previous prime is 20918629. The next prime is 20918699. The reversal of 20918668 is 86681902.

It is a self number, because there is not a number n which added to its sum of digits gives 20918668.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2038 + ... + 6781.

It is an arithmetic number, because the mean of its divisors is an integer number (3056130).

Almost surely, 2^20918668 is an apocalyptic number.

It is an amenable number.

20918668 is a deficient number, since it is larger than the sum of its proper divisors (15754892).

20918668 is a wasteful number, since it uses less digits than its factorization.

20918668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9416 (or 9414 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 20918668 is about 4573.6930373605. The cubic root of 20918668 is about 275.5357841009.

The spelling of 20918668 in words is "twenty million, nine hundred eighteen thousand, six hundred sixty-eight".