81973887120 has 120 divisors (see below), whose sum is σ = 291489542136. Its totient is φ = 20573835264.

The previous prime is 81973887097. The next prime is 81973887179. The reversal of 81973887120 is 2178837918.

It is a happy number.

81973887120 is a `hidden beast` number, since 8 + 197 + 388 + 71 + 2 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 27015524496 + 54958362624 = 164364^2 + 234432^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3336367 + ... + 3360846.

Almost surely, 2^81973887120 is an apocalyptic number.

81973887120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81973887120 is an abundant number, since it is smaller than the sum of its proper divisors (209515655016).

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

81973887120 is a wasteful number, since it uses less digits than its factorization.

81973887120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6697249 (or 6697240 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 54.

The spelling of 81973887120 in words is "eighty-one billion, nine hundred seventy-three million, eight hundred eighty-seven thousand, one hundred twenty".