21493659813 has 16 divisors (see below), whose sum is σ = 29349620352. Its totient is φ = 13987400000.

The previous prime is 21493659799. The next prime is 21493659829. The reversal of 21493659813 is 31895639412.

It is a cyclic number.

It is not a de Polignac number, because 21493659813 - 2⁸ = 21493659557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21493659853) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 478038 + ... + 521063.

It is an arithmetic number, because the mean of its divisors is an integer number (1834351272).

Almost surely, 2^21493659813 is an apocalyptic number.

It is an amenable number.

21493659813 is a deficient number, since it is larger than the sum of its proper divisors (7855960539).

21493659813 is a wasteful number, since it uses less digits than its factorization.

21493659813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999276.

The product of its digits is 1399680, while the sum is 51.

The spelling of 21493659813 in words is "twenty-one billion, four hundred ninety-three million, six hundred fifty-nine thousand, eight hundred thirteen".