20724520 has 16 divisors (see below), whose sum is σ = 46630260. Its totient is φ = 8289792.

The previous prime is 20724511. The next prime is 20724521. The reversal of 20724520 is 2542702.

It can be written as a sum of positive squares in 2 ways, for example, as 19131876 + 1592644 = 4374^2 + 1262^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20724491 and 20724500.

It is not an unprimeable number, because it can be changed into a prime (20724521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259017 + ... + 259096.

Almost surely, 2^20724520 is an apocalyptic number.

20724520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20724520 is an abundant number, since it is smaller than the sum of its proper divisors (25905740).

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

20724520 is a wasteful number, since it uses less digits than its factorization.

20724520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518124 (or 518120 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 22.

The square root of 20724520 is about 4552.4191371182. The cubic root of 20724520 is about 274.6807093186.

The spelling of 20724520 in words is "twenty million, seven hundred twenty-four thousand, five hundred twenty".