20720984 has 16 divisors (see below), whose sum is σ = 39679200. Its totient is φ = 10139872.

The previous prime is 20720971. The next prime is 20721013. The reversal of 20720984 is 48902702.

It is a self number, because there is not a number n which added to its sum of digits gives 20720984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27179 + ... + 27930.

It is an arithmetic number, because the mean of its divisors is an integer number (2479950).

Almost surely, 2^20720984 is an apocalyptic number.

It is an amenable number.

20720984 is a deficient number, since it is larger than the sum of its proper divisors (18958216).

20720984 is a wasteful number, since it uses less digits than its factorization.

20720984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55162 (or 55158 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 20720984 is about 4552.0307556079. The cubic root of 20720984 is about 274.6650865003.

The spelling of 20720984 in words is "twenty million, seven hundred twenty thousand, nine hundred eighty-four".