20556680 has 16 divisors (see below), whose sum is σ = 46252620. Its totient is φ = 8222656.

The previous prime is 20556673. The next prime is 20556691. The reversal of 20556680 is 8665502.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19945156 + 611524 = 4466^2 + 782^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256919 + ... + 256998.

Almost surely, 2^20556680 is an apocalyptic number.

20556680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20556680 is an abundant number, since it is smaller than the sum of its proper divisors (25695940).

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

20556680 is a wasteful number, since it uses less digits than its factorization.

20556680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513928 (or 513924 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 20556680 is about 4533.9475074156. The cubic root of 20556680 is about 273.9371870152.

The spelling of 20556680 in words is "twenty million, five hundred fifty-six thousand, six hundred eighty".