21219166 has 8 divisors (see below), whose sum is σ = 31869720. Its totient is φ = 10595928.

The previous prime is 21219161. The next prime is 21219169. The reversal of 21219166 is 66191212.

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 (21219161) 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, 4761 + ... + 8068.

It is an arithmetic number, because the mean of its divisors is an integer number (3983715).

Almost surely, 2^21219166 is an apocalyptic number.

21219166 is a deficient number, since it is larger than the sum of its proper divisors (10650554).

21219166 is a wasteful number, since it uses less digits than its factorization.

21219166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13658.

The product of its digits is 1296, while the sum is 28.

The square root of 21219166 is about 4606.4265977002. The cubic root of 21219166 is about 276.8488795004.

The spelling of 21219166 in words is "twenty-one million, two hundred nineteen thousand, one hundred sixty-six".