21244273 has 4 divisors (see below), whose sum is σ = 21762468. Its totient is φ = 20726080.

The previous prime is 21244259. The next prime is 21244277. The reversal of 21244273 is 37244212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1236544 + 20007729 = 1112^2 + 4473^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21244273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21244277) 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, 259036 + ... + 259117.

It is an arithmetic number, because the mean of its divisors is an integer number (5440617).

Almost surely, 2^21244273 is an apocalyptic number.

It is an amenable number.

21244273 is a deficient number, since it is larger than the sum of its proper divisors (518195).

21244273 is an equidigital number, since it uses as much as digits as its factorization.

21244273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518194.

The product of its digits is 2688, while the sum is 25.

The square root of 21244273 is about 4609.1510064219. The cubic root of 21244273 is about 276.9580277606.

Adding to 21244273 its reverse (37244212), we get a palindrome (58488485).

The spelling of 21244273 in words is "twenty-one million, two hundred forty-four thousand, two hundred seventy-three".