816717680640 has 312 divisors, whose sum is σ = 2857468749408. Its totient is φ = 215750737920.

The previous prime is 816717680587. The next prime is 816717680693. The reversal of 816717680640 is 46086717618.

It is an interprime number because it is at equal distance from previous prime (816717680587) and next prime (816717680693).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19701535 + ... + 19742945.

It is an arithmetic number, because the mean of its divisors is an integer number (9158553684).

Almost surely, 2^816717680640 is an apocalyptic number.

816717680640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816717680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1428734374704).

816717680640 is an abundant number, since it is smaller than the sum of its proper divisors (2040751068768).

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

816717680640 is a wasteful number, since it uses less digits than its factorization.

816717680640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41553 (or 41528 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The spelling of 816717680640 in words is "eight hundred sixteen billion, seven hundred seventeen million, six hundred eighty thousand, six hundred forty".