20931000 has 64 divisors (see below), whose sum is σ = 65314080. Its totient is φ = 5580800.

The previous prime is 20930999. The next prime is 20931047. The reversal of 20931000 is 13902.

It is a super-2 number, since 2×20931000² = 876213522000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

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, 489 + ... + 6488.

Almost surely, 2^20931000 is an apocalyptic number.

20931000 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 20931000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32657040).

20931000 is an abundant number, since it is smaller than the sum of its proper divisors (44383080).

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

20931000 is a wasteful number, since it uses less digits than its factorization.

20931000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7001 (or 6987 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 15.

The square root of 20931000 is about 4575.0409834230. The cubic root of 20931000 is about 275.5899182009.

Adding to 20931000 its reverse (13902), we get a palindrome (20944902).

The spelling of 20931000 in words is "twenty million, nine hundred thirty-one thousand".