21244255 has 8 divisors (see below), whose sum is σ = 25974432. Its totient is φ = 16674528.

The previous prime is 21244247. The next prime is 21244259. The reversal of 21244255 is 55244212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21244255 - 2³ = 21244247 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 (21244259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39819 + ... + 40348.

It is an arithmetic number, because the mean of its divisors is an integer number (3246804).

Almost surely, 2^21244255 is an apocalyptic number.

21244255 is a deficient number, since it is larger than the sum of its proper divisors (4730177).

21244255 is an equidigital number, since it uses as much as digits as its factorization.

21244255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80225.

The product of its digits is 3200, while the sum is 25.

The square root of 21244255 is about 4609.1490537842. The cubic root of 21244255 is about 276.9579495396.

Adding to 21244255 its reverse (55244212), we get a palindrome (76488467).

The spelling of 21244255 in words is "twenty-one million, two hundred forty-four thousand, two hundred fifty-five".