20931900 has 72 divisors (see below), whose sum is σ = 66079104. Its totient is φ = 5073600.

The previous prime is 20931893. The next prime is 20931917. The reversal of 20931900 is 913902.

It is a happy number.

It is a super-2 number, since 2×20931900² = 876288875220000, 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 23 ways as a sum of consecutive naturals, for example, 129 + ... + 6471.

Almost surely, 2^20931900 is an apocalyptic number.

20931900 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 20931900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33039552).

20931900 is an abundant number, since it is smaller than the sum of its proper divisors (45147204).

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

20931900 is a wasteful number, since it uses less digits than its factorization.

20931900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6371 (or 6364 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 20931900 is about 4575.1393421403. The cubic root of 20931900 is about 275.5938681216.

It can be divided in two parts, 2093 and 1900, that added together give a palindrome (3993).

The spelling of 20931900 in words is "twenty million, nine hundred thirty-one thousand, nine hundred".