20018556 has 48 divisors (see below), whose sum is σ = 54163200. Its totient is φ = 6381936.

The previous prime is 20018543. The next prime is 20018567. The reversal of 20018556 is 65581002.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1546 + ... + 6513.

It is an arithmetic number, because the mean of its divisors is an integer number (1128400).

Almost surely, 2^20018556 is an apocalyptic number.

It is an amenable number.

20018556 is an abundant number, since it is smaller than the sum of its proper divisors (34144644).

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

20018556 is a wasteful number, since it uses less digits than its factorization.

20018556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8095 (or 8087 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 20018556 is about 4474.2100978832. The cubic root of 20018556 is about 271.5256835994.

Adding to 20018556 its reverse (65581002), we get a palindrome (85599558).

The spelling of 20018556 in words is "twenty million, eighteen thousand, five hundred fifty-six".