21928166 has 16 divisors (see below), whose sum is σ = 37287600. Its totient is φ = 9587808.

The previous prime is 21928133. The next prime is 21928169. The reversal of 21928166 is 66182912.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928169) 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 in 7 ways as a sum of consecutive naturals, for example, 21701 + ... + 22688.

It is an arithmetic number, because the mean of its divisors is an integer number (2330475).

Almost surely, 2^21928166 is an apocalyptic number.

21928166 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21928166 is a deficient number, since it is larger than the sum of its proper divisors (15359434).

21928166 is a wasteful number, since it uses less digits than its factorization.

21928166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44423.

The product of its digits is 10368, while the sum is 35.

The square root of 21928166 is about 4682.7519686612. The cubic root of 21928166 is about 279.8986282696.

The spelling of 21928166 in words is "twenty-one million, nine hundred twenty-eight thousand, one hundred sixty-six".