21204073643 has 8 divisors (see below), whose sum is σ = 21240370800. Its totient is φ = 21167803008.

The previous prime is 21204073619. The next prime is 21204073669. The reversal of 21204073643 is 34637040212.

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-21204073643 is a prime.

It is a super-2 number, since 2×21204073643² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21204073673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2165663 + ... + 2175431.

It is an arithmetic number, because the mean of its divisors is an integer number (2655046350).

Almost surely, 2^21204073643 is an apocalyptic number.

21204073643 is a deficient number, since it is larger than the sum of its proper divisors (36297157).

21204073643 is an equidigital number, since it uses as much as digits as its factorization.

21204073643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13261.

The product of its (nonzero) digits is 24192, while the sum is 32.

The spelling of 21204073643 in words is "twenty-one billion, two hundred four million, seventy-three thousand, six hundred forty-three".