2181687287867 has 4 divisors (see below), whose sum is σ = 2181703860456. Its totient is φ = 2181670715280.

The previous prime is 2181687287839. The next prime is 2181687287893. The reversal of 2181687287867 is 7687827861812.

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 2181687287867 - 2²⁸ = 2181418852411 is a prime.

It is a super-2 number, since 2×2181687287867² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2181687287867.

It is not an unprimeable number, because it can be changed into a prime (2181687287267) 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, 8087234 + ... + 8352647.

It is an arithmetic number, because the mean of its divisors is an integer number (545425965114).

Almost surely, 2^{2181687287867} is an apocalyptic number.

2181687287867 is a deficient number, since it is larger than the sum of its proper divisors (16572589).

2181687287867 is a wasteful number, since it uses less digits than its factorization.

2181687287867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16572588.

The product of its digits is 202309632, while the sum is 71.

The spelling of 2181687287867 in words is "two trillion, one hundred eighty-one billion, six hundred eighty-seven million, two hundred eighty-seven thousand, eight hundred sixty-seven".