21688194139843 has 24 divisors (see below), whose sum is σ = 28678603842560. Its totient is φ = 16010423550000.

The previous prime is 21688194139819. The next prime is 21688194139877. The reversal of 21688194139843 is 34893149188612.

It is not a de Polignac number, because 21688194139843 - 2⁵ = 21688194139811 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21688194139343) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 673823283 + ... + 673855468.

Almost surely, 2^{21688194139843} is an apocalyptic number.

21688194139843 is a deficient number, since it is larger than the sum of its proper divisors (6990409702717).

21688194139843 is a wasteful number, since it uses less digits than its factorization.

21688194139843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1347678799 (or 1347678788 counting only the distinct ones).

The product of its digits is 71663616, while the sum is 67.

The spelling of 21688194139843 in words is "twenty-one trillion, six hundred eighty-eight billion, one hundred ninety-four million, one hundred thirty-nine thousand, eight hundred forty-three".