18871905887 has 4 divisors (see below), whose sum is σ = 19982018016. Its totient is φ = 17761793760.

The previous prime is 18871905883. The next prime is 18871905893. The reversal of 18871905887 is 78850917881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78850917881 = 3001 ⋅26274881.

It is a cyclic number.

It is not a de Polignac number, because 18871905887 - 2² = 18871905883 is a prime.

It is a super-2 number, since 2×18871905887² (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 (18871905883) 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, 555056039 + ... + 555056072.

It is an arithmetic number, because the mean of its divisors is an integer number (4995504504).

Almost surely, 2^18871905887 is an apocalyptic number.

18871905887 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

18871905887 is a deficient number, since it is larger than the sum of its proper divisors (1110112129).

18871905887 is a wasteful number, since it uses less digits than its factorization.

18871905887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1110112128.

The product of its (nonzero) digits is 9031680, while the sum is 62.

The spelling of 18871905887 in words is "eighteen billion, eight hundred seventy-one million, nine hundred five thousand, eight hundred eighty-seven".