21493667453 has 2 divisors, whose sum is σ = 21493667454. Its totient is φ = 21493667452.

The previous prime is 21493667389. The next prime is 21493667471. The reversal of 21493667453 is 35476639412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16687989124 + 4805678329 = 129182^2 + 69323^2 .

It is a cyclic number.

It is not a de Polignac number, because 21493667453 - 2⁶ = 21493667389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21493667653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10746833726 + 10746833727.

It is an arithmetic number, because the mean of its divisors is an integer number (10746833727).

Almost surely, 2^21493667453 is an apocalyptic number.

It is an amenable number.

21493667453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21493667453 is an equidigital number, since it uses as much as digits as its factorization.

21493667453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 50.

The spelling of 21493667453 in words is "twenty-one billion, four hundred ninety-three million, six hundred sixty-seven thousand, four hundred fifty-three".