81856110908 has 24 divisors (see below), whose sum is σ = 168291585840. Its totient is φ = 34345221120.

The previous prime is 81856110893. The next prime is 81856110923. The reversal of 81856110908 is 80901165818.

It is an interprime number because it is at equal distance from previous prime (81856110893) and next prime (81856110923).

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, 71551973 + ... + 71553116.

It is an arithmetic number, because the mean of its divisors is an integer number (7012149410).

Almost surely, 2^81856110908 is an apocalyptic number.

It is an amenable number.

81856110908 is an abundant number, since it is smaller than the sum of its proper divisors (86435474932).

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

81856110908 is a wasteful number, since it uses less digits than its factorization.

81856110908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143105117 (or 143105115 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 47.

The spelling of 81856110908 in words is "eighty-one billion, eight hundred fifty-six million, one hundred ten thousand, nine hundred eight".