20556870 has 32 divisors (see below), whose sum is σ = 49459680. Its totient is φ = 5468160.

The previous prime is 20556863. The next prime is 20556883. The reversal of 20556870 is 7865502.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18696 + ... + 19764.

It is an arithmetic number, because the mean of its divisors is an integer number (1545615).

Almost surely, 2^20556870 is an apocalyptic number.

20556870 is an abundant number, since it is smaller than the sum of its proper divisors (28902810).

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

20556870 is a wasteful number, since it uses less digits than its factorization.

20556870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720.

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 20556870 is about 4533.9684604108. The cubic root of 20556870 is about 273.9380309892.

It can be divided in two parts, 205 and 56870, that added together give a palindrome (57075).

The spelling of 20556870 in words is "twenty million, five hundred fifty-six thousand, eight hundred seventy".