21382253 has 4 divisors (see below), whose sum is σ = 21391968. Its totient is φ = 21372540.

The previous prime is 21382247. The next prime is 21382271. The reversal of 21382253 is 35228312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21382253 - 2¹² = 21378157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382453) 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 3 ways as a sum of consecutive naturals, for example, 200 + ... + 6542.

It is an arithmetic number, because the mean of its divisors is an integer number (5347992).

Almost surely, 2^21382253 is an apocalyptic number.

It is an amenable number.

21382253 is a deficient number, since it is larger than the sum of its proper divisors (9715).

21382253 is an equidigital number, since it uses as much as digits as its factorization.

21382253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9714.

The product of its digits is 2880, while the sum is 26.

The square root of 21382253 is about 4624.0948303425. The cubic root of 21382253 is about 277.5563416699.

The spelling of 21382253 in words is "twenty-one million, three hundred eighty-two thousand, two hundred fifty-three".