81363386599 has 4 divisors (see below), whose sum is σ = 88760058120. Its totient is φ = 73966715080.

The previous prime is 81363386591. The next prime is 81363386617. The reversal of 81363386599 is 99568336318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81363386599 - 2³ = 81363386591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81363386591) 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, 3698335744 + ... + 3698335765.

It is an arithmetic number, because the mean of its divisors is an integer number (22190014530).

Almost surely, 2^81363386599 is an apocalyptic number.

81363386599 is a deficient number, since it is larger than the sum of its proper divisors (7396671521).

81363386599 is a wasteful number, since it uses less digits than its factorization.

81363386599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7396671520.

The product of its digits is 25194240, while the sum is 61.

The spelling of 81363386599 in words is "eighty-one billion, three hundred sixty-three million, three hundred eighty-six thousand, five hundred ninety-nine".