21522166 has 8 divisors (see below), whose sum is σ = 32616360. Its totient is φ = 10650048.

The previous prime is 21522161. The next prime is 21522173. The reversal of 21522166 is 66122512.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21522166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21522161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55276 + ... + 55663.

It is an arithmetic number, because the mean of its divisors is an integer number (4077045).

Almost surely, 2^21522166 is an apocalyptic number.

21522166 is a deficient number, since it is larger than the sum of its proper divisors (11094194).

21522166 is a wasteful number, since it uses less digits than its factorization.

21522166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111038.

The product of its digits is 1440, while the sum is 25.

The square root of 21522166 is about 4639.1988532504. The cubic root of 21522166 is about 278.1604149827.

Adding to 21522166 its reverse (66122512), we get a palindrome (87644678).

The spelling of 21522166 in words is "twenty-one million, five hundred twenty-two thousand, one hundred sixty-six".