20909920 has 24 divisors (see below), whose sum is σ = 49400064. Its totient is φ = 8363904.

The previous prime is 20909897. The next prime is 20909923. The reversal of 20909920 is 2990902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20909923) 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 in 3 ways as a sum of consecutive naturals, for example, 65184 + ... + 65503.

It is an arithmetic number, because the mean of its divisors is an integer number (2058336).

Almost surely, 2^20909920 is an apocalyptic number.

20909920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20909920 is an abundant number, since it is smaller than the sum of its proper divisors (28490144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20909920 is a wasteful number, since it uses less digits than its factorization.

20909920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130702 (or 130694 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 20909920 is about 4572.7365985808. The cubic root of 20909920 is about 275.4973698782.

The spelling of 20909920 in words is "twenty million, nine hundred nine thousand, nine hundred twenty".