21766161 has 8 divisors (see below), whose sum is σ = 29147040. Its totient is φ = 14448032.

The previous prime is 21766141. The next prime is 21766163. The reversal of 21766161 is 16166712.

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

It is a cyclic number.

It is not a de Polignac number, because 21766161 - 2⁶ = 21766097 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21766163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14871 + ... + 16268.

It is an arithmetic number, because the mean of its divisors is an integer number (3643380).

Almost surely, 2^21766161 is an apocalyptic number.

It is an amenable number.

21766161 is a deficient number, since it is larger than the sum of its proper divisors (7380879).

21766161 is a wasteful number, since it uses less digits than its factorization.

21766161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31375.

The product of its digits is 3024, while the sum is 30.

The square root of 21766161 is about 4665.4218458785. The cubic root of 21766161 is about 279.2076279788.

The spelling of 21766161 in words is "twenty-one million, seven hundred sixty-six thousand, one hundred sixty-one".