21330275 has 6 divisors (see below), whose sum is σ = 26449572. Its totient is φ = 17064200.

The previous prime is 21330271. The next prime is 21330299. The reversal of 21330275 is 57203312.

It is not a de Polignac number, because 21330275 - 2² = 21330271 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 21330275.

It is not an unprimeable number, because it can be changed into a prime (21330271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 426581 + ... + 426630.

It is an arithmetic number, because the mean of its divisors is an integer number (4408262).

Almost surely, 2^21330275 is an apocalyptic number.

21330275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21330275 is a deficient number, since it is larger than the sum of its proper divisors (5119297).

21330275 is an equidigital number, since it uses as much as digits as its factorization.

21330275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853221 (or 853216 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21330275 is about 4618.4710673555. The cubic root of 21330275 is about 277.3312557950.

Adding to 21330275 its reverse (57203312), we get a palindrome (78533587).

The spelling of 21330275 in words is "twenty-one million, three hundred thirty thousand, two hundred seventy-five".