21545166 has 16 divisors (see below), whose sum is σ = 43218000. Its totient is φ = 7160448.

The previous prime is 21545149. The next prime is 21545179. The reversal of 21545166 is 66154512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3051 + ... + 7238.

It is an arithmetic number, because the mean of its divisors is an integer number (2701125).

Almost surely, 2^21545166 is an apocalyptic number.

21545166 is an abundant number, since it is smaller than the sum of its proper divisors (21672834).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21545166 is a wasteful number, since it uses less digits than its factorization.

21545166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10643.

The product of its digits is 7200, while the sum is 30.

The square root of 21545166 is about 4641.6770676125. The cubic root of 21545166 is about 278.2594665358.

Adding to 21545166 its reverse (66154512), we get a palindrome (87699678).

The spelling of 21545166 in words is "twenty-one million, five hundred forty-five thousand, one hundred sixty-six".