20556628 has 12 divisors (see below), whose sum is σ = 36345652. Its totient is φ = 10172160.

The previous prime is 20556619. The next prime is 20556647. The reversal of 20556628 is 82665502.

It can be written as a sum of positive squares in 2 ways, for example, as 16548624 + 4008004 = 4068^2 + 2002^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20556593 and 20556602.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 26103 + ... + 26878.

Almost surely, 2^20556628 is an apocalyptic number.

It is an amenable number.

20556628 is a deficient number, since it is larger than the sum of its proper divisors (15789024).

20556628 is a wasteful number, since it uses less digits than its factorization.

20556628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53082 (or 53080 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 34.

The square root of 20556628 is about 4533.9417728948. The cubic root of 20556628 is about 273.9369560320.

The spelling of 20556628 in words is "twenty million, five hundred fifty-six thousand, six hundred twenty-eight".