81733398786 has 120 divisors (see below), whose sum is σ = 202713102900. Its totient is φ = 24468179328.

The previous prime is 81733398743. The next prime is 81733398811. The reversal of 81733398786 is 68789333718.

81733398786 is a `hidden beast` number, since 8 + 173 + 3 + 398 + 78 + 6 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 37913931225 + 43819467561 = 194715^2 + 209331^2 .

It is a super-2 number, since 2×81733398786² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 2868940 + ... + 2897288.

Almost surely, 2^81733398786 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81733398786, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101356551450).

81733398786 is an abundant number, since it is smaller than the sum of its proper divisors (120979704114).

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

81733398786 is a wasteful number, since it uses less digits than its factorization.

81733398786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28450 (or 28404 counting only the distinct ones).

The product of its digits is 36578304, while the sum is 63.

The spelling of 81733398786 in words is "eighty-one billion, seven hundred thirty-three million, three hundred ninety-eight thousand, seven hundred eighty-six".