20389920 has 96 divisors (see below), whose sum is σ = 64991808. Its totient is φ = 5372928.

The previous prime is 20389913. The next prime is 20389927. The reversal of 20389920 is 2998302.

It is an interprime number because it is at equal distance from previous prime (20389913) and next prime (20389927).

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (20389927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51162 + ... + 51558.

It is an arithmetic number, because the mean of its divisors is an integer number (676998).

Almost surely, 2^20389920 is an apocalyptic number.

20389920 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 20389920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32495904).

20389920 is an abundant number, since it is smaller than the sum of its proper divisors (44601888).

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

20389920 is a wasteful number, since it uses less digits than its factorization.

20389920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 514 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 20389920 is about 4515.5199036213. The cubic root of 20389920 is about 273.1944300516.

The spelling of 20389920 in words is "twenty million, three hundred eighty-nine thousand, nine hundred twenty".