21311221453 has 2 divisors, whose sum is σ = 21311221454. Its totient is φ = 21311221452.

The previous prime is 21311221447. The next prime is 21311221499. The reversal of 21311221453 is 35412211312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11000443689 + 10310777764 = 104883^2 + 101542^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21311221453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311221153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655610726 + 10655610727.

It is an arithmetic number, because the mean of its divisors is an integer number (10655610727).

Almost surely, 2^21311221453 is an apocalyptic number.

It is an amenable number.

21311221453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311221453 is an equidigital number, since it uses as much as digits as its factorization.

21311221453 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

Adding to 21311221453 its reverse (35412211312), we get a palindrome (56723432765).

The spelling of 21311221453 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-one thousand, four hundred fifty-three".