21322825 has 6 divisors (see below), whose sum is σ = 26440334. Its totient is φ = 17058240.

The previous prime is 21322799. The next prime is 21322849. The reversal of 21322825 is 52822312.

It can be written as a sum of positive squares in 3 ways, for example, as 61504 + 21261321 = 248^2 + 4611^2 .

It is not a de Polignac number, because 21322825 - 2⁵ = 21322793 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 852913 = 21322825 / (2 + 1 + 3 + 2 + 2 + 8 + 2 + 5).

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 21322825.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 426432 + ... + 426481.

Almost surely, 2^21322825 is an apocalyptic number.

21322825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21322825 is a deficient number, since it is larger than the sum of its proper divisors (5117509).

21322825 is an equidigital number, since it uses as much as digits as its factorization.

21322825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 852923 (or 852918 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21322825 is about 4617.6644529459. The cubic root of 21322825 is about 277.2989643150.

The spelling of 21322825 in words is "twenty-one million, three hundred twenty-two thousand, eight hundred twenty-five".