21986895 has 64 divisors (see below), whose sum is σ = 43130880. Its totient is φ = 9341568.

The previous prime is 21986879. The next prime is 21986897. The reversal of 21986895 is 59868912.

It is a happy number.

It is not a de Polignac number, because 21986895 - 2⁴ = 21986879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21986897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 205432 + ... + 205538.

It is an arithmetic number, because the mean of its divisors is an integer number (673920).

Almost surely, 2^21986895 is an apocalyptic number.

21986895 is a deficient number, since it is larger than the sum of its proper divisors (21143985).

21986895 is a wasteful number, since it uses less digits than its factorization.

21986895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244.

The product of its digits is 311040, while the sum is 48.

The square root of 21986895 is about 4689.0185540260. The cubic root of 21986895 is about 280.1482845517.

The spelling of 21986895 in words is "twenty-one million, nine hundred eighty-six thousand, eight hundred ninety-five".