20445620 has 72 divisors (see below), whose sum is σ = 48698496. Its totient is φ = 7193472.

The previous prime is 20445619. The next prime is 20445629. The reversal of 20445620 is 2654402.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20445629) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77609 + ... + 77871.

It is an arithmetic number, because the mean of its divisors is an integer number (676368).

Almost surely, 2^20445620 is an apocalyptic number.

20445620 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 20445620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24349248).

20445620 is an abundant number, since it is smaller than the sum of its proper divisors (28252876).

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

20445620 is a wasteful number, since it uses less digits than its factorization.

20445620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20445620 is about 4521.6833148729. The cubic root of 20445620 is about 273.4429694362.

The spelling of 20445620 in words is "twenty million, four hundred forty-five thousand, six hundred twenty".