21825321 has 32 divisors (see below), whose sum is σ = 35235840. Its totient is φ = 11746944.

The previous prime is 21825289. The next prime is 21825337. The reversal of 21825321 is 12352812.

It is not a de Polignac number, because 21825321 - 2⁵ = 21825289 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21825291 and 21825300.

It is not an unprimeable number, because it can be changed into a prime (21825341) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 34950 + ... + 35568.

It is an arithmetic number, because the mean of its divisors is an integer number (1101120).

Almost surely, 2^21825321 is an apocalyptic number.

21825321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21825321 is a deficient number, since it is larger than the sum of its proper divisors (13410519).

21825321 is a wasteful number, since it uses less digits than its factorization.

21825321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725.

The product of its digits is 960, while the sum is 24.

The square root of 21825321 is about 4671.7578062224. The cubic root of 21825321 is about 279.4603594350.

It can be divided in two parts, 2182 and 5321, that added together give a triangular number (7503 = T₁₂₂).

The spelling of 21825321 in words is "twenty-one million, eight hundred twenty-five thousand, three hundred twenty-one".