18691869187 has 4 divisors (see below), whose sum is σ = 18692378320. Its totient is φ = 18691360056.

The previous prime is 18691869167. The next prime is 18691869193. The reversal of 18691869187 is 78196819681.

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: 78196819681 = 74381 ⋅1051301.

It is a cyclic number.

It is not a de Polignac number, because 18691869187 - 2²⁷ = 18557651459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18691869167) 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, 194823 + ... + 274480.

It is an arithmetic number, because the mean of its divisors is an integer number (4673094580).

Almost surely, 2^18691869187 is an apocalyptic number.

18691869187 is a deficient number, since it is larger than the sum of its proper divisors (509133).

18691869187 is an equidigital number, since it uses as much as digits as its factorization.

18691869187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509132.

The product of its digits is 10450944, while the sum is 64.

The spelling of 18691869187 in words is "eighteen billion, six hundred ninety-one million, eight hundred sixty-nine thousand, one hundred eighty-seven".