20331720 has 48 divisors (see below), whose sum is σ = 66079260. Its totient is φ = 5421696.

The previous prime is 20331679. The next prime is 20331721. The reversal of 20331720 is 2713302.

It can be written as a sum of positive squares in 2 ways, for example, as 17489124 + 2842596 = 4182^2 + 1686^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20331693 and 20331702.

It is not an unprimeable number, because it can be changed into a prime (20331721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27879 + ... + 28598.

Almost surely, 2^20331720 is an apocalyptic number.

20331720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20331720 is an abundant number, since it is smaller than the sum of its proper divisors (45747540).

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

20331720 is a wasteful number, since it uses less digits than its factorization.

20331720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56494 (or 56487 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 18.

The square root of 20331720 is about 4509.0708577267. The cubic root of 20331720 is about 272.9342513645.

The spelling of 20331720 in words is "twenty million, three hundred thirty-one thousand, seven hundred twenty".