20390920 has 64 divisors (see below), whose sum is σ = 50595840. Its totient is φ = 7395520.

The previous prime is 20390911. The next prime is 20390941. The reversal of 20390920 is 2909302.

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, 53049 + ... + 53431.

It is an arithmetic number, because the mean of its divisors is an integer number (790560).

Almost surely, 2^20390920 is an apocalyptic number.

20390920 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 20390920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25297920).

20390920 is an abundant number, since it is smaller than the sum of its proper divisors (30204920).

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

20390920 is a wasteful number, since it uses less digits than its factorization.

20390920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 20390920 is about 4515.6306314844. The cubic root of 20390920 is about 273.1988961467.

The spelling of 20390920 in words is "twenty million, three hundred ninety thousand, nine hundred twenty".