21244233 has 4 divisors (see below), whose sum is σ = 28325648. Its totient is φ = 14162820.

The previous prime is 21244231. The next prime is 21244243. The reversal of 21244233 is 33244212.

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.

It is not a de Polignac number, because 21244233 - 2¹ = 21244231 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21244231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3540703 + ... + 3540708.

It is an arithmetic number, because the mean of its divisors is an integer number (7081412).

Almost surely, 2^21244233 is an apocalyptic number.

It is an amenable number.

21244233 is a deficient number, since it is larger than the sum of its proper divisors (7081415).

21244233 is an equidigital number, since it uses as much as digits as its factorization.

21244233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7081414.

The product of its digits is 1152, while the sum is 21.

The square root of 21244233 is about 4609.1466672259. The cubic root of 21244233 is about 276.9578539360.

Subtracting from 21244233 its sum of digits (21), we obtain a palindrome (21244212).

Adding to 21244233 its reverse (33244212), we get a palindrome (54488445).

The spelling of 21244233 in words is "twenty-one million, two hundred forty-four thousand, two hundred thirty-three".