20891886 has 16 divisors (see below), whose sum is σ = 42066000. Its totient is φ = 6916928.

The previous prime is 20891879. The next prime is 20891891. The reversal of 20891886 is 68819802.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10791 + ... + 12578.

It is an arithmetic number, because the mean of its divisors is an integer number (2629125).

Almost surely, 2^20891886 is an apocalyptic number.

20891886 is an abundant number, since it is smaller than the sum of its proper divisors (21174114).

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

20891886 is a wasteful number, since it uses less digits than its factorization.

20891886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23523.

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 20891886 is about 4570.7642686973. The cubic root of 20891886 is about 275.4181451437.

The spelling of 20891886 in words is "twenty million, eight hundred ninety-one thousand, eight hundred eighty-six".