20407920 has 160 divisors (see below), whose sum is σ = 70662144. Its totient is φ = 4838400.

The previous prime is 20407903. The next prime is 20407921. The reversal of 20407920 is 2970402.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20407921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 96615 + ... + 96825.

Almost surely, 2^20407920 is an apocalyptic number.

20407920 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 20407920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35331072).

20407920 is an abundant number, since it is smaller than the sum of its proper divisors (50254224).

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

20407920 is a wasteful number, since it uses less digits than its factorization.

20407920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 20407920 is about 4517.5125899105. The cubic root of 20407920 is about 273.2747974327.

The spelling of 20407920 in words is "twenty million, four hundred seven thousand, nine hundred twenty".