812731778688 has 128 divisors (see below), whose sum is σ = 2211947781120. Its totient is φ = 264281066496.

The previous prime is 812731778671. The next prime is 812731778699. The reversal of 812731778688 is 886877137218.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×812731778688² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5467395 + ... + 5614077.

It is an arithmetic number, because the mean of its divisors is an integer number (17280842040).

Almost surely, 2^812731778688 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 812731778688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1105973890560).

812731778688 is an abundant number, since it is smaller than the sum of its proper divisors (1399216002432).

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

812731778688 is a wasteful number, since it uses less digits than its factorization.

812731778688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147054 (or 147042 counting only the distinct ones).

The product of its digits is 50577408, while the sum is 66.

The spelling of 812731778688 in words is "eight hundred twelve billion, seven hundred thirty-one million, seven hundred seventy-eight thousand, six hundred eighty-eight".