20789864 has 8 divisors (see below), whose sum is σ = 38981010. Its totient is φ = 10394928.

The previous prime is 20789863. The next prime is 20789869. The reversal of 20789864 is 46898702.

It can be written as a sum of positive squares in only one way, i.e., 16337764 + 4452100 = 4042^2 + 2110^2 .

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 (20789863) by changing a digit.

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, 1299359 + ... + 1299374.

Almost surely, 2^20789864 is an apocalyptic number.

It is an amenable number.

20789864 is a deficient number, since it is larger than the sum of its proper divisors (18191146).

20789864 is a wasteful number, since it uses less digits than its factorization.

20789864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2598739 (or 2598735 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 20789864 is about 4559.5903324751. The cubic root of 20789864 is about 274.9690940474.

The spelling of 20789864 in words is "twenty million, seven hundred eighty-nine thousand, eight hundred sixty-four".