21251255453 has 2 divisors, whose sum is σ = 21251255454. Its totient is φ = 21251255452.

The previous prime is 21251255401. The next prime is 21251255533. The reversal of 21251255453 is 35455215212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21117321124 + 133934329 = 145318^2 + 11573^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21251255453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21251251453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625627726 + 10625627727.

It is an arithmetic number, because the mean of its divisors is an integer number (10625627727).

Almost surely, 2^21251255453 is an apocalyptic number.

It is an amenable number.

21251255453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251255453 is an equidigital number, since it uses as much as digits as its factorization.

21251255453 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60000, while the sum is 35.

The spelling of 21251255453 in words is "twenty-one billion, two hundred fifty-one million, two hundred fifty-five thousand, four hundred fifty-three".