81630856212 has 24 divisors (see below), whose sum is σ = 190596450912. Its totient is φ = 27192506400.

The previous prime is 81630856193. The next prime is 81630856259. The reversal of 81630856212 is 21265803618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2203239 + ... + 2239982.

It is an arithmetic number, because the mean of its divisors is an integer number (7941518788).

Almost surely, 2^81630856212 is an apocalyptic number.

It is an amenable number.

81630856212 is an abundant number, since it is smaller than the sum of its proper divisors (108965594700).

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

81630856212 is a wasteful number, since it uses less digits than its factorization.

81630856212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4444759 (or 4444757 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 81630856212 in words is "eighty-one billion, six hundred thirty million, eight hundred fifty-six thousand, two hundred twelve".