20939668 has 6 divisors (see below), whose sum is σ = 36644426. Its totient is φ = 10469832.

The previous prime is 20939657. The next prime is 20939671. The reversal of 20939668 is 86693902.

It can be written as a sum of positive squares in only one way, i.e., 19820304 + 1119364 = 4452^2 + 1058^2 .

It is a congruent number.

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 as a sum of consecutive naturals, namely, 2617455 + ... + 2617462.

Almost surely, 2^20939668 is an apocalyptic number.

It is an amenable number.

20939668 is a deficient number, since it is larger than the sum of its proper divisors (15704758).

20939668 is a wasteful number, since it uses less digits than its factorization.

20939668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5234921 (or 5234919 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 20939668 is about 4575.9881992855. The cubic root of 20939668 is about 275.6279556212.

The spelling of 20939668 in words is "twenty million, nine hundred thirty-nine thousand, six hundred sixty-eight".