21311453 has 2 divisors, whose sum is σ = 21311454. Its totient is φ = 21311452.

The previous prime is 21311447. The next prime is 21311467. The reversal of 21311453 is 35411312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21279769 + 31684 = 4613^2 + 178^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21311453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655726 + 10655727.

It is an arithmetic number, because the mean of its divisors is an integer number (10655727).

Almost surely, 2^21311453 is an apocalyptic number.

It is an amenable number.

21311453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311453 is an equidigital number, since it uses as much as digits as its factorization.

21311453 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 20.

The square root of 21311453 is about 4616.4329303045. The cubic root of 21311453 is about 277.2496587064.

Adding to 21311453 its reverse (35411312), we get a palindrome (56722765).

The spelling of 21311453 in words is "twenty-one million, three hundred eleven thousand, four hundred fifty-three".