20555680 has 24 divisors (see below), whose sum is σ = 48563172. Its totient is φ = 8222208.

The previous prime is 20555651. The next prime is 20555681. The reversal of 20555680 is 8655502.

It can be written as a sum of positive squares in 2 ways, for example, as 19465744 + 1089936 = 4412^2 + 1044^2 .

It is not an unprimeable number, because it can be changed into a prime (20555681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64077 + ... + 64396.

Almost surely, 2^20555680 is an apocalyptic number.

20555680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20555680 is an abundant number, since it is smaller than the sum of its proper divisors (28007492).

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

20555680 is a wasteful number, since it uses less digits than its factorization.

20555680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128488 (or 128480 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

The square root of 20555680 is about 4533.8372268973. The cubic root of 20555680 is about 273.9327449616.

The spelling of 20555680 in words is "twenty million, five hundred fifty-five thousand, six hundred eighty".