81211117612 has 24 divisors (see below), whose sum is σ = 149757531840. Its totient is φ = 38427768720.

The previous prime is 81211117609. The next prime is 81211117619. The reversal of 81211117612 is 21671111218.

It is not an unprimeable number, because it can be changed into a prime (81211117619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 492214 + ... + 636157.

It is an arithmetic number, because the mean of its divisors is an integer number (6239897160).

Almost surely, 2^81211117612 is an apocalyptic number.

It is an amenable number.

81211117612 is a deficient number, since it is larger than the sum of its proper divisors (68546414228).

81211117612 is a wasteful number, since it uses less digits than its factorization.

81211117612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1129341 (or 1129339 counting only the distinct ones).

The product of its digits is 1344, while the sum is 31.

The spelling of 81211117612 in words is "eighty-one billion, two hundred eleven million, one hundred seventeen thousand, six hundred twelve".