20978792 has 8 divisors (see below), whose sum is σ = 39335250. Its totient is φ = 10489392.

The previous prime is 20978791. The next prime is 20978819. The reversal of 20978792 is 29787902.

It can be written as a sum of positive squares in only one way, i.e., 14394436 + 6584356 = 3794^2 + 2566^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (20978791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1311167 + ... + 1311182.

Almost surely, 2^20978792 is an apocalyptic number.

It is an amenable number.

20978792 is a deficient number, since it is larger than the sum of its proper divisors (18356458).

20978792 is a wasteful number, since it uses less digits than its factorization.

20978792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2622355 (or 2622351 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 44.

The square root of 20978792 is about 4580.2611279271. The cubic root of 20978792 is about 275.7995113335.

The spelling of 20978792 in words is "twenty million, nine hundred seventy-eight thousand, seven hundred ninety-two".