21918166 has 8 divisors (see below), whose sum is σ = 32924304. Its totient is φ = 10943400.

The previous prime is 21918161. The next prime is 21918173. The reversal of 21918166 is 66181912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21918161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6010 + ... + 8941.

It is an arithmetic number, because the mean of its divisors is an integer number (4115538).

Almost surely, 2^21918166 is an apocalyptic number.

21918166 is a deficient number, since it is larger than the sum of its proper divisors (11006138).

21918166 is a wasteful number, since it uses less digits than its factorization.

21918166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15686.

The product of its digits is 5184, while the sum is 34.

The square root of 21918166 is about 4681.6840986978. The cubic root of 21918166 is about 279.8560739908.

The spelling of 21918166 in words is "twenty-one million, nine hundred eighteen thousand, one hundred sixty-six".