20556385 has 16 divisors (see below), whose sum is σ = 26156160. Its totient is φ = 15465600.

The previous prime is 20556307. The next prime is 20556391. The reversal of 20556385 is 58365502.

It is a happy number.

It is not a de Polignac number, because 20556385 - 2¹¹ = 20554337 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20556385.

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, 13629 + ... + 15061.

It is an arithmetic number, because the mean of its divisors is an integer number (1634760).

Almost surely, 2^20556385 is an apocalyptic number.

It is an amenable number.

20556385 is a deficient number, since it is larger than the sum of its proper divisors (5599775).

20556385 is a wasteful number, since it uses less digits than its factorization.

20556385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608.

The product of its (nonzero) digits is 36000, while the sum is 34.

The square root of 20556385 is about 4533.9149749416. The cubic root of 20556385 is about 273.9358766244.

The spelling of 20556385 in words is "twenty million, five hundred fifty-six thousand, three hundred eighty-five".