20556872 has 36 divisors (see below), whose sum is σ = 45033705. Its totient is φ = 8771616.

The previous prime is 20556863. The next prime is 20556883. The reversal of 20556872 is 27865502.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 15476356 + 5080516 = 3934^2 + 2254^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3206.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 89654 + ... + 89882.

Almost surely, 2^20556872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20556872

20556872 is an abundant number, since it is smaller than the sum of its proper divisors (24476833).

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

20556872 is an equidigital number, since it uses as much as digits as its factorization.

20556872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 35.

The square root of 20556872 is about 4533.9686809681. The cubic root of 20556872 is about 273.9380398731.

The spelling of 20556872 in words is "twenty million, five hundred fifty-six thousand, eight hundred seventy-two".