2181687 has 8 divisors (see below), whose sum is σ = 3002880. Its totient is φ = 1407480.

The previous prime is 2181671. The next prime is 2181689. The reversal of 2181687 is 7861812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2181687 - 2⁴ = 2181671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11637 + ... + 11822.

It is an arithmetic number, because the mean of its divisors is an integer number (375360).

2^2181687 is an apocalyptic number.

2181687 is a deficient number, since it is larger than the sum of its proper divisors (821193).

2181687 is a wasteful number, since it uses less digits than its factorization.

2181687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23493.

The product of its digits is 5376, while the sum is 33.

The square root of 2181687 is about 1477.0534858291. The cubic root of 2181687 is about 129.6972639961.

The spelling of 2181687 in words is "two million, one hundred eighty-one thousand, six hundred eighty-seven".