21605787716734 has 16 divisors (see below), whose sum is σ = 36105162498720. Its totient is φ = 9628043332320.

The previous prime is 21605787716729. The next prime is 21605787716783. The reversal of 21605787716734 is 43761778750612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14327444682 + ... + 14327446189.

It is an arithmetic number, because the mean of its divisors is an integer number (2256572656170).

Almost surely, 2^{21605787716734} is an apocalyptic number.

21605787716734 is a deficient number, since it is larger than the sum of its proper divisors (14499374781986).

21605787716734 is a wasteful number, since it uses less digits than its factorization.

21605787716734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28654890915.

The product of its (nonzero) digits is 82978560, while the sum is 64.

The spelling of 21605787716734 in words is "twenty-one trillion, six hundred five billion, seven hundred eighty-seven million, seven hundred sixteen thousand, seven hundred thirty-four".