20018920 has 16 divisors (see below), whose sum is σ = 45042660. Its totient is φ = 8007552.

The previous prime is 20018909. The next prime is 20018923. The reversal of 20018920 is 2981002.

It can be written as a sum of positive squares in 2 ways, for example, as 19766916 + 252004 = 4446^2 + 502^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20018891 and 20018900.

It is not an unprimeable number, because it can be changed into a prime (20018923) 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 3 ways as a sum of consecutive naturals, for example, 250197 + ... + 250276.

Almost surely, 2^20018920 is an apocalyptic number.

20018920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20018920 is an abundant number, since it is smaller than the sum of its proper divisors (25023740).

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

20018920 is a wasteful number, since it uses less digits than its factorization.

20018920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500484 (or 500480 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 20018920 is about 4474.2507752695. The cubic root of 20018920 is about 271.5273293183.

Adding to 20018920 its reverse (2981002), we get a palindrome (22999922).

The spelling of 20018920 in words is "twenty million, eighteen thousand, nine hundred twenty".