81621180104 has 16 divisors (see below), whose sum is σ = 153084894720. Its totient is φ = 40798541520.

The previous prime is 81621180071. The next prime is 81621180107. The reversal of 81621180104 is 40108112618.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81621180107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1477244 + ... + 1531499.

It is an arithmetic number, because the mean of its divisors is an integer number (9567805920).

Almost surely, 2^81621180104 is an apocalyptic number.

It is an amenable number.

81621180104 is a deficient number, since it is larger than the sum of its proper divisors (71463714616).

81621180104 is a wasteful number, since it uses less digits than its factorization.

81621180104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3012140 (or 3012136 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 32.

The spelling of 81621180104 in words is "eighty-one billion, six hundred twenty-one million, one hundred eighty thousand, one hundred four".