21791659356 has 18 divisors (see below), whose sum is σ = 55084472352. Its totient is φ = 7263886440.

The previous prime is 21791659339. The next prime is 21791659391. The reversal of 21791659356 is 65395619712.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 302661900 + ... + 302661971.

It is an arithmetic number, because the mean of its divisors is an integer number (3060248464).

Almost surely, 2^21791659356 is an apocalyptic number.

It is an amenable number.

21791659356 is an abundant number, since it is smaller than the sum of its proper divisors (33292812996).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21791659356 is a wasteful number, since it uses less digits than its factorization.

21791659356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605323881 (or 605323876 counting only the distinct ones).

The product of its digits is 3061800, while the sum is 54.

The spelling of 21791659356 in words is "twenty-one billion, seven hundred ninety-one million, six hundred fifty-nine thousand, three hundred fifty-six".