18877388887 has 4 divisors (see below), whose sum is σ = 21574158736. Its totient is φ = 16180619040.

The previous prime is 18877388857. The next prime is 18877388903. The reversal of 18877388887 is 78888377881.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18877388887 - 2¹⁵ = 18877356119 is a prime.

It is a super-2 number, since 2×18877388887² (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 (18877388857) 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, 1348384914 + ... + 1348384927.

It is an arithmetic number, because the mean of its divisors is an integer number (5393539684).

Almost surely, 2^18877388887 is an apocalyptic number.

18877388887 is a deficient number, since it is larger than the sum of its proper divisors (2696769849).

18877388887 is an equidigital number, since it uses as much as digits as its factorization.

18877388887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2696769848.

The product of its digits is 269746176, while the sum is 73.

The spelling of 18877388887 in words is "eighteen billion, eight hundred seventy-seven million, three hundred eighty-eight thousand, eight hundred eighty-seven".