18351685085 has 4 divisors (see below), whose sum is σ = 22022022108. Its totient is φ = 14681348064.

The previous prime is 18351685081. The next prime is 18351685103. The reversal of 18351685085 is 58058615381.

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 6526862521 + 11824822564 = 80789^2 + 108742^2 .

It is a cyclic number.

It is not a de Polignac number, because 18351685085 - 2² = 18351685081 is a prime.

It is a super-2 number, since 2×18351685085² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18351685081) 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, 1835168504 + ... + 1835168513.

It is an arithmetic number, because the mean of its divisors is an integer number (5505505527).

Almost surely, 2^18351685085 is an apocalyptic number.

It is an amenable number.

18351685085 is a deficient number, since it is larger than the sum of its proper divisors (3670337023).

18351685085 is an equidigital number, since it uses as much as digits as its factorization.

18351685085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3670337022.

The product of its (nonzero) digits is 1152000, while the sum is 50.

The spelling of 18351685085 in words is "eighteen billion, three hundred fifty-one million, six hundred eighty-five thousand, eighty-five".