81656009612 has 12 divisors (see below), whose sum is σ = 143441357136. Its totient is φ = 40672764720.

The previous prime is 81656009609. The next prime is 81656009651. The reversal of 81656009612 is 21690065618.

It is a super-3 number, since 3×81656009612³ (a number of 34 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38808839 + ... + 38810942.

It is an arithmetic number, because the mean of its divisors is an integer number (11953446428).

Almost surely, 2^81656009612 is an apocalyptic number.

It is an amenable number.

81656009612 is a deficient number, since it is larger than the sum of its proper divisors (61785347524).

81656009612 is a wasteful number, since it uses less digits than its factorization.

81656009612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77620048 (or 77620046 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 81656009612 in words is "eighty-one billion, six hundred fifty-six million, nine thousand, six hundred twelve".