21432534553 has 2 divisors, whose sum is σ = 21432534554. Its totient is φ = 21432534552.

The previous prime is 21432534551. The next prime is 21432534569. The reversal of 21432534553 is 35543523412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11157063129 + 10275471424 = 105627^2 + 101368^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432534553 - 2¹ = 21432534551 is a prime.

Together with 21432534551, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21432534551) 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, 10716267276 + 10716267277.

It is an arithmetic number, because the mean of its divisors is an integer number (10716267277).

Almost surely, 2^21432534553 is an apocalyptic number.

It is an amenable number.

21432534553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432534553 is an equidigital number, since it uses as much as digits as its factorization.

21432534553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216000, while the sum is 37.

It can be divided in two parts, 21432 and 534553, that added together give a triangular number (555985 = T₁₀₅₄).

The spelling of 21432534553 in words is "twenty-one billion, four hundred thirty-two million, five hundred thirty-four thousand, five hundred fifty-three".