21885706 has 4 divisors (see below), whose sum is σ = 32828562. Its totient is φ = 10942852.

The previous prime is 21885697. The next prime is 21885707. The reversal of 21885706 is 60758812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12638025 + 9247681 = 3555^2 + 3041^2 .

It is not an unprimeable number, because it can be changed into a prime (21885707) 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 as a sum of consecutive naturals, namely, 5471425 + ... + 5471428.

Almost surely, 2^21885706 is an apocalyptic number.

21885706 is a deficient number, since it is larger than the sum of its proper divisors (10942856).

21885706 is a wasteful number, since it uses less digits than its factorization.

21885706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10942855.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 21885706 is about 4678.2161130072. The cubic root of 21885706 is about 279.7178535412.

The spelling of 21885706 in words is "twenty-one million, eight hundred eighty-five thousand, seven hundred six".