21709837865688 has 64 divisors (see below), whose sum is σ = 62877808335360. Its totient is φ = 6117840804096.

The previous prime is 21709837865647. The next prime is 21709837865741. The reversal of 21709837865688 is 88656873890712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 885092020 + ... + 885116547.

It is an arithmetic number, because the mean of its divisors is an integer number (982465755240).

Almost surely, 2^{21709837865688} is an apocalyptic number.

21709837865688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21709837865688 is an abundant number, since it is smaller than the sum of its proper divisors (41167970469672).

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

21709837865688 is a wasteful number, since it uses less digits than its factorization.

21709837865688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1770208656 (or 1770208652 counting only the distinct ones).

The product of its (nonzero) digits is 1950842880, while the sum is 78.

The spelling of 21709837865688 in words is "twenty-one trillion, seven hundred nine billion, eight hundred thirty-seven million, eight hundred sixty-five thousand, six hundred eighty-eight".