816357978922464 has 432 divisors, whose sum is σ = 2679757708642560. Its totient is φ = 244249775827200.

The previous prime is 816357978922439. The next prime is 816357978922469. The reversal of 816357978922464 is 464229879753618.

816357978922464 is a `hidden beast` number, since 8 + 1 + 6 + 3 + 5 + 79 + 7 + 89 + 2 + 2 + 464 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816357978922469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 68839399 + ... + 79822169.

It is an arithmetic number, because the mean of its divisors is an integer number (6203142844080).

Almost surely, 2^{816357978922464} 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 816357978922464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1339878854321280).

816357978922464 is an abundant number, since it is smaller than the sum of its proper divisors (1863399729720096).

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

816357978922464 is a wasteful number, since it uses less digits than its factorization.

816357978922464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10982897 (or 10982866 counting only the distinct ones).

The product of its digits is 8778792960, while the sum is 81.

The spelling of 816357978922464 in words is "eight hundred sixteen trillion, three hundred fifty-seven billion, nine hundred seventy-eight million, nine hundred twenty-two thousand, four hundred sixty-four".