18685859861 has 4 divisors (see below), whose sum is σ = 18689404800. Its totient is φ = 18682314924.

The previous prime is 18685859849. The next prime is 18685859867. The reversal of 18685859861 is 16895858681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16895858681 = 13 ⋅1299681437.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18685859861 is a prime.

It is a super-2 number, since 2×18685859861² (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 (18685859867) 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, 1764551 + ... + 1775108.

It is an arithmetic number, because the mean of its divisors is an integer number (4672351200).

Almost surely, 2^18685859861 is an apocalyptic number.

It is an amenable number.

18685859861 is a deficient number, since it is larger than the sum of its proper divisors (3544939).

18685859861 is an equidigital number, since it uses as much as digits as its factorization.

18685859861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3544938.

The product of its digits is 33177600, while the sum is 65.

The spelling of 18685859861 in words is "eighteen billion, six hundred eighty-five million, eight hundred fifty-nine thousand, eight hundred sixty-one".