21161886 has 32 divisors (see below), whose sum is σ = 44686080. Its totient is φ = 6667584.

The previous prime is 21161869. The next prime is 21161887. The reversal of 21161886 is 68816112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11421 + ... + 13143.

It is an arithmetic number, because the mean of its divisors is an integer number (1396440).

Almost surely, 2^21161886 is an apocalyptic number.

21161886 is an abundant number, since it is smaller than the sum of its proper divisors (23524194).

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

21161886 is a wasteful number, since it uses less digits than its factorization.

21161886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1840.

The product of its digits is 4608, while the sum is 33.

The square root of 21161886 is about 4600.2049954323. The cubic root of 21161886 is about 276.5995421099.

Adding to 21161886 its reverse (68816112), we get a palindrome (89977998).

The spelling of 21161886 in words is "twenty-one million, one hundred sixty-one thousand, eight hundred eighty-six".