20415720 has 128 divisors (see below), whose sum is σ = 68947200. Its totient is φ = 4798464.

The previous prime is 20415713. The next prime is 20415737. The reversal of 20415720 is 2751402.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35596 + ... + 36164.

It is an arithmetic number, because the mean of its divisors is an integer number (538650).

Almost surely, 2^20415720 is an apocalyptic number.

20415720 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 20415720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34473600).

20415720 is an abundant number, since it is smaller than the sum of its proper divisors (48531480).

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

20415720 is a wasteful number, since it uses less digits than its factorization.

20415720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 615 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 20415720 is about 4518.3758143829. The cubic root of 20415720 is about 273.3096086223.

The spelling of 20415720 in words is "twenty million, four hundred fifteen thousand, seven hundred twenty".