21042534745 has 16 divisors (see below), whose sum is σ = 26666381952. Its totient is φ = 15908104960.

The previous prime is 21042534727. The next prime is 21042534767. The reversal of 21042534745 is 54743524012.

It is not a de Polignac number, because 21042534745 - 2¹⁷ = 21042403673 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 1092736 + ... + 1111825.

It is an arithmetic number, because the mean of its divisors is an integer number (1666648872).

Almost surely, 2^21042534745 is an apocalyptic number.

It is an amenable number.

21042534745 is a deficient number, since it is larger than the sum of its proper divisors (5623847207).

21042534745 is a wasteful number, since it uses less digits than its factorization.

21042534745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2204672.

The product of its (nonzero) digits is 134400, while the sum is 37.

The spelling of 21042534745 in words is "twenty-one billion, forty-two million, five hundred thirty-four thousand, seven hundred forty-five".