81171827039 has 2 divisors, whose sum is σ = 81171827040. Its totient is φ = 81171827038.

The previous prime is 81171827017. The next prime is 81171827063. The reversal of 81171827039 is 93072817118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81171827039 - 2⁸ = 81171826783 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81171826984 and 81171827002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81171827339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40585913519 + 40585913520.

It is an arithmetic number, because the mean of its divisors is an integer number (40585913520).

Almost surely, 2^81171827039 is an apocalyptic number.

81171827039 is a deficient number, since it is larger than the sum of its proper divisors (1).

81171827039 is an equidigital number, since it uses as much as digits as its factorization.

81171827039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 47.

The spelling of 81171827039 in words is "eighty-one billion, one hundred seventy-one million, eight hundred twenty-seven thousand, thirty-nine".