21042051539 has 2 divisors, whose sum is σ = 21042051540. Its totient is φ = 21042051538.

The previous prime is 21042051517. The next prime is 21042051551. The reversal of 21042051539 is 93515024012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21042051539 - 2²⁴ = 21025274323 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21042051839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521025769 + 10521025770.

It is an arithmetic number, because the mean of its divisors is an integer number (10521025770).

Almost surely, 2^21042051539 is an apocalyptic number.

21042051539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21042051539 is an equidigital number, since it uses as much as digits as its factorization.

21042051539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21042051539 in words is "twenty-one billion, forty-two million, fifty-one thousand, five hundred thirty-nine".