2181917331 has 40 divisors (see below), whose sum is σ = 3631440384. Its totient is φ = 1294213680.

The previous prime is 2181917327. The next prime is 2181917351. The reversal of 2181917331 is 1337191812.

It is not a de Polignac number, because 2181917331 - 2² = 2181917327 is a prime.

It is a super-2 number, since 2×2181917331² = 9521526478636327122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (2181917351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 15826 + ... + 67928.

Almost surely, 2^2181917331 is an apocalyptic number.

2181917331 is a deficient number, since it is larger than the sum of its proper divisors (1449523053).

2181917331 is a wasteful number, since it uses less digits than its factorization.

2181917331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52173 (or 52164 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 2181917331 is about 46710.9979662178. The cubic root of 2181917331 is about 1297.0182808636.

It can be divided in two parts, 218191 and 7331, that added together give a palindrome (225522).

The spelling of 2181917331 in words is "two billion, one hundred eighty-one million, nine hundred seventeen thousand, three hundred thirty-one".