21328166 has 32 divisors (see below), whose sum is σ = 35562240. Its totient is φ = 9547776.

The previous prime is 21328163. The next prime is 21328171. The reversal of 21328166 is 66182312.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21328163) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 95531 + ... + 95753.

It is an arithmetic number, because the mean of its divisors is an integer number (1111320).

Almost surely, 2^21328166 is an apocalyptic number.

21328166 is a deficient number, since it is larger than the sum of its proper divisors (14234074).

21328166 is a wasteful number, since it uses less digits than its factorization.

21328166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368.

The product of its digits is 3456, while the sum is 29.

The square root of 21328166 is about 4618.2427393977. The cubic root of 21328166 is about 277.3221152519.

The spelling of 21328166 in words is "twenty-one million, three hundred twenty-eight thousand, one hundred sixty-six".