21223166 has 8 divisors (see below), whose sum is σ = 32575224. Its totient is φ = 10364760.

The previous prime is 21223159. The next prime is 21223187. The reversal of 21223166 is 66132212.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123305 + ... + 123476.

It is an arithmetic number, because the mean of its divisors is an integer number (4071903).

Almost surely, 2^21223166 is an apocalyptic number.

21223166 is a deficient number, since it is larger than the sum of its proper divisors (11352058).

21223166 is a wasteful number, since it uses less digits than its factorization.

21223166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246826.

The product of its digits is 864, while the sum is 23.

The square root of 21223166 is about 4606.8607532679. The cubic root of 21223166 is about 276.8662745596.

Adding to 21223166 its reverse (66132212), we get a palindrome (87355378).

The spelling of 21223166 in words is "twenty-one million, two hundred twenty-three thousand, one hundred sixty-six".