20811320 has 32 divisors (see below), whose sum is σ = 48863520. Its totient is φ = 7962240.

The previous prime is 20811283. The next prime is 20811331. The reversal of 20811320 is 2311802.

It is a super-2 number, since 2×20811320² = 866222080284800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10391 + ... + 12230.

It is an arithmetic number, because the mean of its divisors is an integer number (1526985).

Almost surely, 2^20811320 is an apocalyptic number.

20811320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20811320 is an abundant number, since it is smaller than the sum of its proper divisors (28052200).

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

20811320 is a wasteful number, since it uses less digits than its factorization.

20811320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22655 (or 22651 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 20811320 is about 4561.9425686872. The cubic root of 20811320 is about 275.0636546861.

The spelling of 20811320 in words is "twenty million, eight hundred eleven thousand, three hundred twenty".