79921866816 has 504 divisors, whose sum is σ = 264089839104. Its totient is φ = 23063040000.

The previous prime is 79921866793. The next prime is 79921866833. The reversal of 79921866816 is 61866812997.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 153400636 + ... + 153401156.

It is an arithmetic number, because the mean of its divisors is an integer number (523987776).

Almost surely, 2^79921866816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 79921866816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132044919552).

79921866816 is an abundant number, since it is smaller than the sum of its proper divisors (184167972288).

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

79921866816 is a wasteful number, since it uses less digits than its factorization.

79921866816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663 (or 639 counting only the distinct ones).

The product of its digits is 15676416, while the sum is 63.

The spelling of 79921866816 in words is "seventy-nine billion, nine hundred twenty-one million, eight hundred sixty-six thousand, eight hundred sixteen".