21635678668 has 6 divisors (see below), whose sum is σ = 37862437676. Its totient is φ = 10817839332.

The previous prime is 21635678591. The next prime is 21635678681. The reversal of 21635678668 is 86687653612.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2704459830 + ... + 2704459837.

Almost surely, 2^21635678668 is an apocalyptic number.

It is an amenable number.

21635678668 is a deficient number, since it is larger than the sum of its proper divisors (16226759008).

21635678668 is a wasteful number, since it uses less digits than its factorization.

21635678668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5408919671 (or 5408919669 counting only the distinct ones).

The product of its digits is 17418240, while the sum is 58.

The spelling of 21635678668 in words is "twenty-one billion, six hundred thirty-five million, six hundred seventy-eight thousand, six hundred sixty-eight".