21670166 has 16 divisors (see below), whose sum is σ = 37234080. Its totient is φ = 9265920.

The previous prime is 21670141. The next prime is 21670177. The reversal of 21670166 is 66107612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5606 + ... + 8646.

It is an arithmetic number, because the mean of its divisors is an integer number (2327130).

Almost surely, 2^21670166 is an apocalyptic number.

21670166 is a deficient number, since it is larger than the sum of its proper divisors (15563914).

21670166 is a wasteful number, since it uses less digits than its factorization.

21670166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3559.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 21670166 is about 4655.1225547777. The cubic root of 21670166 is about 278.7965612262.

Adding to 21670166 its reverse (66107612), we get a palindrome (87777778).

The spelling of 21670166 in words is "twenty-one million, six hundred seventy thousand, one hundred sixty-six".