20813688 has 96 divisors (see below), whose sum is σ = 65576160. Its totient is φ = 5840640.

The previous prime is 20813669. The next prime is 20813693. The reversal of 20813688 is 88631802.

It is a super-2 number, since 2×20813688² = 866419216322688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 30406 + ... + 31082.

It is an arithmetic number, because the mean of its divisors is an integer number (683085).

Almost surely, 2^20813688 is an apocalyptic number.

20813688 is a gapful number since it is divisible by the number (28) 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 20813688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32788080).

20813688 is an abundant number, since it is smaller than the sum of its proper divisors (44762472).

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

20813688 is a wasteful number, since it uses less digits than its factorization.

20813688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 20813688 is about 4562.2020998636. The cubic root of 20813688 is about 275.0740869257.

The spelling of 20813688 in words is "twenty million, eight hundred thirteen thousand, six hundred eighty-eight".