91819099997 has 4 divisors (see below), whose sum is σ = 93551535900. Its totient is φ = 90086664096.

The previous prime is 91819099979. The next prime is 91819100029. The reversal of 91819099997 is 79999091819.

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

It can be written as a sum of positive squares in 2 ways, for example, as 34350544921 + 57468555076 = 185339^2 + 239726^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91819099997 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91819099997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91819099907) 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, 866217872 + ... + 866217977.

It is an arithmetic number, because the mean of its divisors is an integer number (23387883975).

Almost surely, 2^91819099997 is an apocalyptic number.

It is an amenable number.

91819099997 is a deficient number, since it is larger than the sum of its proper divisors (1732435903).

91819099997 is a wasteful number, since it uses less digits than its factorization.

91819099997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1732435902.

The product of its (nonzero) digits is 29760696, while the sum is 71.

The spelling of 91819099997 in words is "ninety-one billion, eight hundred nineteen million, ninety-nine thousand, nine hundred ninety-seven".