20518320 has 160 divisors (see below), whose sum is σ = 69424128. Its totient is φ = 4993024.

The previous prime is 20518307. The next prime is 20518331. The reversal of 20518320 is 2381502.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 191707 + ... + 191813.

Almost surely, 2^20518320 is an apocalyptic number.

20518320 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 20518320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34712064).

20518320 is an abundant number, since it is smaller than the sum of its proper divisors (48905808).

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

20518320 is a wasteful number, since it uses less digits than its factorization.

20518320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 20518320 is about 4529.7152228369. The cubic root of 20518320 is about 273.7666864998.

Adding to 20518320 its reverse (2381502), we get a palindrome (22899822).

The spelling of 20518320 in words is "twenty million, five hundred eighteen thousand, three hundred twenty".