21711166 has 4 divisors (see below), whose sum is σ = 32566752. Its totient is φ = 10855582.

The previous prime is 21711163. The next prime is 21711229. The reversal of 21711166 is 66111712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21711166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21711163) 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 as a sum of consecutive naturals, namely, 5427790 + ... + 5427793.

It is an arithmetic number, because the mean of its divisors is an integer number (8141688).

Almost surely, 2^21711166 is an apocalyptic number.

21711166 is a deficient number, since it is larger than the sum of its proper divisors (10855586).

21711166 is a wasteful number, since it uses less digits than its factorization.

21711166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10855585.

The product of its digits is 504, while the sum is 25.

The square root of 21711166 is about 4659.5242246392. The cubic root of 21711166 is about 278.9722783486.

Adding to 21711166 its reverse (66111712), we get a palindrome (87822878).

The spelling of 21711166 in words is "twenty-one million, seven hundred eleven thousand, one hundred sixty-six".