21688561006499 has 8 divisors (see below), whose sum is σ = 21743066815680. Its totient is φ = 21634104955176.

The previous prime is 21688561006477. The next prime is 21688561006507. The reversal of 21688561006499 is 99460016588612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21688561006499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21688561066499) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11566529 + ... + 13310210.

It is an arithmetic number, because the mean of its divisors is an integer number (2717883351960).

Almost surely, 2^{21688561006499} is an apocalyptic number.

21688561006499 is a deficient number, since it is larger than the sum of its proper divisors (54505809181).

21688561006499 is a wasteful number, since it uses less digits than its factorization.

21688561006499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24878929.

The product of its (nonzero) digits is 44789760, while the sum is 65.

The spelling of 21688561006499 in words is "twenty-one trillion, six hundred eighty-eight billion, five hundred sixty-one million, six thousand, four hundred ninety-nine".