21116453 has 2 divisors, whose sum is σ = 21116454. Its totient is φ = 21116452.

The previous prime is 21116411. The next prime is 21116471. The reversal of 21116453 is 35461112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14876449 + 6240004 = 3857^2 + 2498^2 .

It is a cyclic number.

It is not a de Polignac number, because 21116453 - 2¹⁰ = 21115429 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21116653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558226 + 10558227.

It is an arithmetic number, because the mean of its divisors is an integer number (10558227).

Almost surely, 2^21116453 is an apocalyptic number.

It is an amenable number.

21116453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116453 is an equidigital number, since it uses as much as digits as its factorization.

21116453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 23.

The square root of 21116453 is about 4595.2641926227. The cubic root of 21116453 is about 276.4014540467.

Adding to 21116453 its reverse (35461112), we get a palindrome (56577565).

The spelling of 21116453 in words is "twenty-one million, one hundred sixteen thousand, four hundred fifty-three".