20438720 has 56 divisors (see below), whose sum is σ = 50804064. Its totient is φ = 7817216.

The previous prime is 20438711. The next prime is 20438729. The reversal of 20438720 is 2783402.

It is an interprime number because it is at equal distance from previous prime (20438711) and next prime (20438729).

It is a self number, because there is not a number n which added to its sum of digits gives 20438720.

It is not an unprimeable number, because it can be changed into a prime (20438729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5972 + ... + 8748.

Almost surely, 2^20438720 is an apocalyptic number.

20438720 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 20438720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25402032).

20438720 is an abundant number, since it is smaller than the sum of its proper divisors (30365344).

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

20438720 is a wasteful number, since it uses less digits than its factorization.

20438720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2817 (or 2807 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 20438720 is about 4520.9202603010. The cubic root of 20438720 is about 273.4122054098.

The spelling of 20438720 in words is "twenty million, four hundred thirty-eight thousand, seven hundred twenty".