81347392866780 has 72 divisors (see below), whose sum is σ = 246754728550512. Its totient is φ = 21692552806656.

The previous prime is 81347392866769. The next prime is 81347392866781. The reversal of 81347392866780 is 8766829374318.

81347392866780 is a `hidden beast` number, since 8 + 1 + 3 + 473 + 9 + 2 + 86 + 6 + 78 + 0 = 666.

81347392866780 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81347392866699 and 81347392866708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81347392866781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54629199 + ... + 56098521.

It is an arithmetic number, because the mean of its divisors is an integer number (3427149007646).

Almost surely, 2^{81347392866780} is an apocalyptic number.

It is an amenable number.

81347392866780 is an abundant number, since it is smaller than the sum of its proper divisors (165407335683732).

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

81347392866780 is a wasteful number, since it uses less digits than its factorization.

81347392866780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1776915 (or 1776910 counting only the distinct ones).

The product of its (nonzero) digits is 585252864, while the sum is 72.

The spelling of 81347392866780 in words is "eighty-one trillion, three hundred forty-seven billion, three hundred ninety-two million, eight hundred sixty-six thousand, seven hundred eighty".