2191881 has 8 divisors (see below), whose sum is σ = 2949760. Its totient is φ = 1447632.

The previous prime is 2191873. The next prime is 2191883. The reversal of 2191881 is 1881912.

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

It is not a de Polignac number, because 2191881 - 2³ = 2191873 is a prime.

It is a super-2 number, since 2×2191881² = 9608684636322, which contains 22 as substring.

It is the 1481-st Hogben number.

It is a Duffinian number.

It is a Curzon number.

2191881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2191883) by changing a digit.

It is a nontrivial repunit in base 1480.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3025 + ... + 3678.

It is an arithmetic number, because the mean of its divisors is an integer number (368720).

2^2191881 is an apocalyptic number.

It is an amenable number.

2191881 is a deficient number, since it is larger than the sum of its proper divisors (757879).

2191881 is a wasteful number, since it uses less digits than its factorization.

2191881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6815.

The product of its digits is 1152, while the sum is 30.

The square root of 2191881 is about 1480.5002532928. The cubic root of 2191881 is about 129.8989550118.

The spelling of 2191881 in words is "two million, one hundred ninety-one thousand, eight hundred eighty-one".