18109697257 has 4 divisors (see below), whose sum is σ = 18145276740. Its totient is φ = 18074117776.

The previous prime is 18109697161. The next prime is 18109697261. The reversal of 18109697257 is 75279690181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75279690181 = 125407 ⋅600283.

It can be written as a sum of positive squares in 2 ways, for example, as 7945226496 + 10164470761 = 89136^2 + 100819^2 .

It is a cyclic number.

It is not a de Polignac number, because 18109697257 - 2¹⁹ = 18109172969 is a prime.

It is a super-2 number, since 2×18109697257² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18109697198 and 18109697207.

It is not an unprimeable number, because it can be changed into a prime (18109697057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17788978 + ... + 17789995.

It is an arithmetic number, because the mean of its divisors is an integer number (4536319185).

Almost surely, 2^18109697257 is an apocalyptic number.

It is an amenable number.

18109697257 is a deficient number, since it is larger than the sum of its proper divisors (35579483).

18109697257 is an equidigital number, since it uses as much as digits as its factorization.

18109697257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35579482.

The product of its (nonzero) digits is 1905120, while the sum is 55.

The spelling of 18109697257 in words is "eighteen billion, one hundred nine million, six hundred ninety-seven thousand, two hundred fifty-seven".