21042504431 has 8 divisors (see below), whose sum is σ = 23646426720. Its totient is φ = 18579334752.

The previous prime is 21042504421. The next prime is 21042504437. The reversal of 21042504431 is 13440524012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042504431 is a prime.

It is a super-2 number, since 2×21042504431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21042504431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042504437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35187836 + ... + 35188433.

It is an arithmetic number, because the mean of its divisors is an integer number (2955803340).

Almost surely, 2^21042504431 is an apocalyptic number.

21042504431 is a deficient number, since it is larger than the sum of its proper divisors (2603922289).

21042504431 is a wasteful number, since it uses less digits than its factorization.

21042504431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70376305.

The product of its (nonzero) digits is 3840, while the sum is 26.

The spelling of 21042504431 in words is "twenty-one billion, forty-two million, five hundred four thousand, four hundred thirty-one".