21133325 has 6 divisors (see below), whose sum is σ = 26205354. Its totient is φ = 16906640.

The previous prime is 21133309. The next prime is 21133381. The reversal of 21133325 is 52333112.

It can be written as a sum of positive squares in 3 ways, for example, as 2866249 + 18267076 = 1693^2 + 4274^2 .

It is not a de Polignac number, because 21133325 - 2⁴ = 21133309 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21133297 and 21133306.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 422642 + ... + 422691.

It is an arithmetic number, because the mean of its divisors is an integer number (4367559).

Almost surely, 2^21133325 is an apocalyptic number.

21133325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21133325 is a deficient number, since it is larger than the sum of its proper divisors (5072029).

21133325 is an equidigital number, since it uses as much as digits as its factorization.

21133325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845343 (or 845338 counting only the distinct ones).

The product of its digits is 540, while the sum is 20.

The square root of 21133325 is about 4597.0996291140. The cubic root of 21133325 is about 276.4750491695.

Adding to 21133325 its reverse (52333112), we get a palindrome (73466437).

The spelling of 21133325 in words is "twenty-one million, one hundred thirty-three thousand, three hundred twenty-five".