20907920 has 80 divisors (see below), whose sum is σ = 55389312. Its totient is φ = 7265280.

The previous prime is 20907911. The next prime is 20907937. The reversal of 20907920 is 2970902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×20907920² = 874282237452800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19724 + ... + 20756.

Almost surely, 2^20907920 is an apocalyptic number.

20907920 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 20907920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27694656).

20907920 is an abundant number, since it is smaller than the sum of its proper divisors (34481392).

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

20907920 is a wasteful number, since it uses less digits than its factorization.

20907920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080 (or 1074 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 20907920 is about 4572.5179059245. The cubic root of 20907920 is about 275.4885859723.

The spelling of 20907920 in words is "twenty million, nine hundred seven thousand, nine hundred twenty".