18399549697 has 4 divisors (see below), whose sum is σ = 18467949780. Its totient is φ = 18331149616.

The previous prime is 18399549673. The next prime is 18399549703. The reversal of 18399549697 is 79694599381.

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 2156302096 + 16243247601 = 46436^2 + 127449^2 .

It is a cyclic number.

It is not a de Polignac number, because 18399549697 - 2⁷ = 18399549569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18399549617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34199638 + ... + 34200175.

It is an arithmetic number, because the mean of its divisors is an integer number (4616987445).

Almost surely, 2^18399549697 is an apocalyptic number.

It is an amenable number.

18399549697 is a deficient number, since it is larger than the sum of its proper divisors (68400083).

18399549697 is an equidigital number, since it uses as much as digits as its factorization.

18399549697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68400082.

The product of its digits is 132269760, while the sum is 70.

The spelling of 18399549697 in words is "eighteen billion, three hundred ninety-nine million, five hundred forty-nine thousand, six hundred ninety-seven".