20905920 has 336 divisors, whose sum is σ = 88440768. Its totient is φ = 4423680.

The previous prime is 20905901. The next prime is 20905921. The reversal of 20905920 is 2950902.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20905921) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 342690 + ... + 342750.

Almost surely, 2^20905920 is an apocalyptic number.

20905920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20905920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44220384).

20905920 is an abundant number, since it is smaller than the sum of its proper divisors (67534848).

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

20905920 is a wasteful number, since it uses less digits than its factorization.

20905920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 20905920 is about 4572.2992028081. The cubic root of 20905920 is about 275.4798015062.

The spelling of 20905920 in words is "twenty million, nine hundred five thousand, nine hundred twenty".