20913920 has 36 divisors (see below), whose sum is σ = 50098440. Its totient is φ = 8365056.

The previous prime is 20913887. The next prime is 20913931. The reversal of 20913920 is 2931902.

It is a self number, because there is not a number n which added to its sum of digits gives 20913920.

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, 6890 + ... + 9449.

Almost surely, 2^20913920 is an apocalyptic number.

20913920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20913920 is an abundant number, since it is smaller than the sum of its proper divisors (29184520).

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

20913920 is an equidigital number, since it uses as much as digits as its factorization.

20913920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16360 (or 16346 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 20913920 is about 4573.1739525192. The cubic root of 20913920 is about 275.5149360097.

The spelling of 20913920 in words is "twenty million, nine hundred thirteen thousand, nine hundred twenty".