21243001453 has 2 divisors, whose sum is σ = 21243001454. Its totient is φ = 21243001452.

The previous prime is 21243001369. The next prime is 21243001463. The reversal of 21243001453 is 35410034212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11199353929 + 10043647524 = 105827^2 + 100218^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243001453 - 2¹⁷ = 21242870381 is a prime.

It is a super-2 number, since 2×21243001453² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243001463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621500726 + 10621500727.

It is an arithmetic number, because the mean of its divisors is an integer number (10621500727).

Almost surely, 2^21243001453 is an apocalyptic number.

It is an amenable number.

21243001453 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243001453 is an equidigital number, since it uses as much as digits as its factorization.

21243001453 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21243001453 its reverse (35410034212), we get a palindrome (56653035665).

The spelling of 21243001453 in words is "twenty-one billion, two hundred forty-three million, one thousand, four hundred fifty-three".