81698163907 has 2 divisors, whose sum is σ = 81698163908. Its totient is φ = 81698163906.

The previous prime is 81698163887. The next prime is 81698163919. The reversal of 81698163907 is 70936189618.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81698163907 is a prime.

It is not a weakly prime, because it can be changed into another prime (81698163307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40849081953 + 40849081954.

It is an arithmetic number, because the mean of its divisors is an integer number (40849081954).

Almost surely, 2^81698163907 is an apocalyptic number.

81698163907 is a deficient number, since it is larger than the sum of its proper divisors (1).

81698163907 is an equidigital number, since it uses as much as digits as its factorization.

81698163907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3919104, while the sum is 58.

The spelling of 81698163907 in words is "eighty-one billion, six hundred ninety-eight million, one hundred sixty-three thousand, nine hundred seven".