81610446139 has 2 divisors, whose sum is σ = 81610446140. Its totient is φ = 81610446138.

The previous prime is 81610446131. The next prime is 81610446157. The reversal of 81610446139 is 93164401618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81610446139 - 2³ = 81610446131 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81610446095 and 81610446104.

It is not a weakly prime, because it can be changed into another prime (81610446131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40805223069 + 40805223070.

It is an arithmetic number, because the mean of its divisors is an integer number (40805223070).

Almost surely, 2^81610446139 is an apocalyptic number.

81610446139 is a deficient number, since it is larger than the sum of its proper divisors (1).

81610446139 is an equidigital number, since it uses as much as digits as its factorization.

81610446139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The spelling of 81610446139 in words is "eighty-one billion, six hundred ten million, four hundred forty-six thousand, one hundred thirty-nine".