81100609399 has 2 divisors, whose sum is σ = 81100609400. Its totient is φ = 81100609398.

The previous prime is 81100609397. The next prime is 81100609417. The reversal of 81100609399 is 99390600118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81100609399 - 2¹ = 81100609397 is a prime.

Together with 81100609397, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81100609397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40550304699 + 40550304700.

It is an arithmetic number, because the mean of its divisors is an integer number (40550304700).

Almost surely, 2^81100609399 is an apocalyptic number.

81100609399 is a deficient number, since it is larger than the sum of its proper divisors (1).

81100609399 is an equidigital number, since it uses as much as digits as its factorization.

81100609399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 46.

The spelling of 81100609399 in words is "eighty-one billion, one hundred million, six hundred nine thousand, three hundred ninety-nine".