21439753 has 2 divisors, whose sum is σ = 21439754. Its totient is φ = 21439752.

The previous prime is 21439741. The next prime is 21439783. The reversal of 21439753 is 35793412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12866569 + 8573184 = 3587^2 + 2928^2 .

It is a cyclic number.

It is not a de Polignac number, because 21439753 - 2⁵ = 21439721 is a prime.

It is not a weakly prime, because it can be changed into another prime (21439723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10719876 + 10719877.

It is an arithmetic number, because the mean of its divisors is an integer number (10719877).

Almost surely, 2^21439753 is an apocalyptic number.

It is an amenable number.

21439753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21439753 is an equidigital number, since it uses as much as digits as its factorization.

21439753 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 34.

The square root of 21439753 is about 4630.3080891016. The cubic root of 21439753 is about 277.8049154939.

The spelling of 21439753 in words is "twenty-one million, four hundred thirty-nine thousand, seven hundred fifty-three".