21424885 has 4 divisors (see below), whose sum is σ = 25709868. Its totient is φ = 17139904.

The previous prime is 21424877. The next prime is 21424943. The reversal of 21424885 is 58842412.

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 6625476 + 14799409 = 2574^2 + 3847^2 .

It is a cyclic number.

It is not a de Polignac number, because 21424885 - 2³ = 21424877 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21424885.

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, 2142484 + ... + 2142493.

It is an arithmetic number, because the mean of its divisors is an integer number (6427467).

Almost surely, 2^21424885 is an apocalyptic number.

It is an amenable number.

21424885 is a deficient number, since it is larger than the sum of its proper divisors (4284983).

21424885 is an equidigital number, since it uses as much as digits as its factorization.

21424885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284982.

The product of its digits is 20480, while the sum is 34.

The square root of 21424885 is about 4628.7023019417. The cubic root of 21424885 is about 277.7406834318.

The spelling of 21424885 in words is "twenty-one million, four hundred twenty-four thousand, eight hundred eighty-five".