21666110 has 16 divisors (see below), whose sum is σ = 39062736. Its totient is φ = 8652288.

The previous prime is 21666101. The next prime is 21666121. The reversal of 21666110 is 1166612.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 6494 + ... + 9246.

It is an arithmetic number, because the mean of its divisors is an integer number (2441421).

Almost surely, 2^21666110 is an apocalyptic number.

21666110 is a deficient number, since it is larger than the sum of its proper divisors (17396626).

21666110 is a wasteful number, since it uses less digits than its factorization.

21666110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3547.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21666110 is about 4654.6868852803. The cubic root of 21666110 is about 278.7791660447.

The spelling of 21666110 in words is "twenty-one million, six hundred sixty-six thousand, one hundred ten".