20979668 has 6 divisors (see below), whose sum is σ = 36714426. Its totient is φ = 10489832.

The previous prime is 20979641. The next prime is 20979671. The reversal of 20979668 is 86697902.

It can be written as a sum of positive squares in only one way, i.e., 20775364 + 204304 = 4558^2 + 452^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2622455 + ... + 2622462.

It is an arithmetic number, because the mean of its divisors is an integer number (6119071).

Almost surely, 2^20979668 is an apocalyptic number.

It is an amenable number.

20979668 is a deficient number, since it is larger than the sum of its proper divisors (15734758).

20979668 is a wasteful number, since it uses less digits than its factorization.

20979668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5244921 (or 5244919 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 20979668 is about 4580.3567546644. The cubic root of 20979668 is about 275.8033500834.

The spelling of 20979668 in words is "twenty million, nine hundred seventy-nine thousand, six hundred sixty-eight".