21864485 has 4 divisors (see below), whose sum is σ = 26237388. Its totient is φ = 17491584.

The previous prime is 21864457. The next prime is 21864509. The reversal of 21864485 is 58446812.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7134241 + 14730244 = 2671^2 + 3838^2 .

It is a cyclic number.

It is not a de Polignac number, because 21864485 - 2⁸ = 21864229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2186444 + ... + 2186453.

It is an arithmetic number, because the mean of its divisors is an integer number (6559347).

Almost surely, 2^21864485 is an apocalyptic number.

It is an amenable number.

21864485 is a deficient number, since it is larger than the sum of its proper divisors (4372903).

21864485 is an equidigital number, since it uses as much as digits as its factorization.

21864485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4372902.

The product of its digits is 61440, while the sum is 38.

The square root of 21864485 is about 4675.9474975667. The cubic root of 21864485 is about 279.6274168556.

The spelling of 21864485 in words is "twenty-one million, eight hundred sixty-four thousand, four hundred eighty-five".