18391785097 has 12 divisors (see below), whose sum is σ = 21422830980. Its totient is φ = 15743530656.

The previous prime is 18391785037. The next prime is 18391785127. The reversal of 18391785097 is 79058719381.

It can be written as a sum of positive squares in 2 ways, for example, as 15450241401 + 2941543696 = 124299^2 + 54236^2 .

It is not a de Polignac number, because 18391785097 - 2²⁷ = 18257567369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18391785037) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 210822 + ... + 285007.

It is an arithmetic number, because the mean of its divisors is an integer number (1785235915).

Almost surely, 2^18391785097 is an apocalyptic number.

It is an amenable number.

18391785097 is a deficient number, since it is larger than the sum of its proper divisors (3031045883).

18391785097 is an equidigital number, since it uses as much as digits as its factorization.

18391785097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496600 (or 496593 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 58.

The spelling of 18391785097 in words is "eighteen billion, three hundred ninety-one million, seven hundred eighty-five thousand, ninety-seven".