21918196 has 6 divisors (see below), whose sum is σ = 38356850. Its totient is φ = 10959096.

The previous prime is 21918187. The next prime is 21918233. The reversal of 21918196 is 69181912.

It can be written as a sum of positive squares in only one way, i.e., 17139600 + 4778596 = 4140^2 + 2186^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2739771 + ... + 2739778.

Almost surely, 2^21918196 is an apocalyptic number.

It is an amenable number.

21918196 is a deficient number, since it is larger than the sum of its proper divisors (16438654).

21918196 is a wasteful number, since it uses less digits than its factorization.

21918196 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5479553 (or 5479551 counting only the distinct ones).

The product of its digits is 7776, while the sum is 37.

The square root of 21918196 is about 4681.6873026720. The cubic root of 21918196 is about 279.8562016730.

The spelling of 21918196 in words is "twenty-one million, nine hundred eighteen thousand, one hundred ninety-six".