2181831 has 16 divisors (see below), whose sum is σ = 3110400. Its totient is φ = 1355648.

The previous prime is 2181737. The next prime is 2181833. The reversal of 2181831 is 1381812.

It is not a de Polignac number, because 2181831 - 2¹⁰ = 2180807 is a prime.

It is a super-2 number, since 2×2181831² = 9520773025122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181833) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9010 + ... + 9248.

It is an arithmetic number, because the mean of its divisors is an integer number (194400).

2^2181831 is an apocalyptic number.

2181831 is a deficient number, since it is larger than the sum of its proper divisors (928569).

2181831 is a wasteful number, since it uses less digits than its factorization.

2181831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438.

The product of its digits is 384, while the sum is 24.

The square root of 2181831 is about 1477.1022307207. The cubic root of 2181831 is about 129.7001174447.

The spelling of 2181831 in words is "two million, one hundred eighty-one thousand, eight hundred thirty-one".