21544142539 has 2 divisors, whose sum is σ = 21544142540. Its totient is φ = 21544142538.

The previous prime is 21544142537. The next prime is 21544142549. The reversal of 21544142539 is 93524144512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21544142539 - 2¹ = 21544142537 is a prime.

Together with 21544142537, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21544142533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772071269 + 10772071270.

It is an arithmetic number, because the mean of its divisors is an integer number (10772071270).

Almost surely, 2^21544142539 is an apocalyptic number.

21544142539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21544142539 is an equidigital number, since it uses as much as digits as its factorization.

21544142539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 172800, while the sum is 40.

The spelling of 21544142539 in words is "twenty-one billion, five hundred forty-four million, one hundred forty-two thousand, five hundred thirty-nine".