20556620 has 24 divisors (see below), whose sum is σ = 49336224. Its totient is φ = 7047936.

The previous prime is 20556619. The next prime is 20556647. The reversal of 20556620 is 2665502.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20556620.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 73277 + ... + 73556.

It is an arithmetic number, because the mean of its divisors is an integer number (2055676).

Almost surely, 2^20556620 is an apocalyptic number.

20556620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20556620 is an abundant number, since it is smaller than the sum of its proper divisors (28779604).

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

20556620 is a wasteful number, since it uses less digits than its factorization.

20556620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146849 (or 146847 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 20556620 is about 4533.9408906601. The cubic root of 20556620 is about 273.9369204961.

The spelling of 20556620 in words is "twenty million, five hundred fifty-six thousand, six hundred twenty".