21244723 has 2 divisors, whose sum is σ = 21244724. Its totient is φ = 21244722.

The previous prime is 21244711. The next prime is 21244757. The reversal of 21244723 is 32744212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21244723 - 2²¹ = 19147571 is a prime.

It is not a weakly prime, because it can be changed into another prime (21241723) 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 as a sum of consecutive naturals, namely, 10622361 + 10622362.

It is an arithmetic number, because the mean of its divisors is an integer number (10622362).

Almost surely, 2^21244723 is an apocalyptic number.

21244723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21244723 is an equidigital number, since it uses as much as digits as its factorization.

21244723 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21244723 is about 4609.1998220949. The cubic root of 21244723 is about 276.9599832717.

Adding to 21244723 its reverse (32744212), we get a palindrome (53988935).

The spelling of 21244723 in words is "twenty-one million, two hundred forty-four thousand, seven hundred twenty-three".