20805188 has 6 divisors (see below), whose sum is σ = 36409086. Its totient is φ = 10402592.

The previous prime is 20805167. The next prime is 20805199. The reversal of 20805188 is 88150802.

It can be written as a sum of positive squares in only one way, i.e., 19998784 + 806404 = 4472^2 + 898^2 .

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 as a sum of consecutive naturals, namely, 2600645 + ... + 2600652.

It is an arithmetic number, because the mean of its divisors is an integer number (6068181).

Almost surely, 2^20805188 is an apocalyptic number.

It is an amenable number.

20805188 is a deficient number, since it is larger than the sum of its proper divisors (15603898).

20805188 is a wasteful number, since it uses less digits than its factorization.

20805188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5201301 (or 5201299 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 32.

The square root of 20805188 is about 4561.2704370603. The cubic root of 20805188 is about 275.0366364413.

The spelling of 20805188 in words is "twenty million, eight hundred five thousand, one hundred eighty-eight".