81635871660 has 96 divisors (see below), whose sum is σ = 261825080832. Its totient is φ = 18617464320.

The previous prime is 81635871607. The next prime is 81635871673. The reversal of 81635871660 is 6617853618.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33321 + ... + 405440.

It is an arithmetic number, because the mean of its divisors is an integer number (2727344592).

Almost surely, 2^81635871660 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 81635871660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130912540416).

81635871660 is an abundant number, since it is smaller than the sum of its proper divisors (180189209172).

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

81635871660 is a wasteful number, since it uses less digits than its factorization.

81635871660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439223 (or 439221 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 51.

The spelling of 81635871660 in words is "eighty-one billion, six hundred thirty-five million, eight hundred seventy-one thousand, six hundred sixty".