81805889107 has 2 divisors, whose sum is σ = 81805889108. Its totient is φ = 81805889106.

The previous prime is 81805889069. The next prime is 81805889117. The reversal of 81805889107 is 70198850818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81805889107 - 2²⁷ = 81671671379 is a prime.

It is not a weakly prime, because it can be changed into another prime (81805889117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40902944553 + 40902944554.

It is an arithmetic number, because the mean of its divisors is an integer number (40902944554).

Almost surely, 2^81805889107 is an apocalyptic number.

81805889107 is a deficient number, since it is larger than the sum of its proper divisors (1).

81805889107 is an equidigital number, since it uses as much as digits as its factorization.

81805889107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 55.

The spelling of 81805889107 in words is "eighty-one billion, eight hundred five million, eight hundred eighty-nine thousand, one hundred seven".