81851338008180 has 120 divisors (see below), whose sum is σ = 276522269615592. Its totient is φ = 20148021658368.

The previous prime is 81851338008179. The next prime is 81851338008229. The reversal of 81851338008180 is 8180083315818.

81851338008180 is a `hidden beast` number, since 8 + 1 + 85 + 1 + 3 + 380 + 0 + 8 + 180 = 666.

81851338008180 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 16496822010384 + 65354515997796 = 4061628^2 + 8084214^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1943268067 + ... + 1943310186.

Almost surely, 2^{81851338008180} is an apocalyptic number.

It is an amenable number.

81851338008180 is an abundant number, since it is smaller than the sum of its proper divisors (194670931607412).

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

81851338008180 is a wasteful number, since it uses less digits than its factorization.

81851338008180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3886578287 (or 3886578276 counting only the distinct ones).

The product of its (nonzero) digits is 1474560, while the sum is 54.

The spelling of 81851338008180 in words is "eighty-one trillion, eight hundred fifty-one billion, three hundred thirty-eight million, eight thousand, one hundred eighty".