21865706 has 16 divisors (see below), whose sum is σ = 34966080. Its totient is φ = 10219200.

The previous prime is 21865687. The next prime is 21865721. The reversal of 21865706 is 60756812.

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, 3005 + ... + 7263.

It is an arithmetic number, because the mean of its divisors is an integer number (2185380).

Almost surely, 2^21865706 is an apocalyptic number.

21865706 is a deficient number, since it is larger than the sum of its proper divisors (13100374).

21865706 is a wasteful number, since it uses less digits than its factorization.

21865706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4429.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 21865706 is about 4676.0780575179. The cubic root of 21865706 is about 279.6326219286.

The spelling of 21865706 in words is "twenty-one million, eight hundred sixty-five thousand, seven hundred six".