20205556 has 24 divisors (see below), whose sum is σ = 40631360. Its totient is φ = 8612352.

The previous prime is 20205551. The next prime is 20205557. The reversal of 20205556 is 65550202.

It is a self number, because there is not a number n which added to its sum of digits gives 20205556.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20205551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3535 + ... + 7273.

Almost surely, 2^20205556 is an apocalyptic number.

It is an amenable number.

20205556 is an abundant number, since it is smaller than the sum of its proper divisors (20425804).

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

20205556 is a wasteful number, since it uses less digits than its factorization.

20205556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3943 (or 3941 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 20205556 is about 4495.0590652404. The cubic root of 20205556 is about 272.3685351892.

Adding to 20205556 its reverse (65550202), we get a palindrome (85755758).

The spelling of 20205556 in words is "twenty million, two hundred five thousand, five hundred fifty-six".