21791357217434 has 192 divisors, whose sum is σ = 43014755496960. Its totient is φ = 8208618485760.

The previous prime is 21791357217337. The next prime is 21791357217491. The reversal of 21791357217434 is 43471275319712.

It is a self number, because there is not a number n which added to its sum of digits gives 21791357217434.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5411310929 + ... + 5411314955.

It is an arithmetic number, because the mean of its divisors is an integer number (224035184880).

Almost surely, 2^{21791357217434} is an apocalyptic number.

21791357217434 is a deficient number, since it is larger than the sum of its proper divisors (21223398279526).

21791357217434 is a wasteful number, since it uses less digits than its factorization.

21791357217434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7733 (or 7726 counting only the distinct ones).

The product of its digits is 8890560, while the sum is 56.

The spelling of 21791357217434 in words is "twenty-one trillion, seven hundred ninety-one billion, three hundred fifty-seven million, two hundred seventeen thousand, four hundred thirty-four".