2191831 has 8 divisors (see below), whose sum is σ = 2302560. Its totient is φ = 2082432.

The previous prime is 2191823. The next prime is 2191873. The reversal of 2191831 is 1381912.

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

It is a cyclic number.

It is not a de Polignac number, because 2191831 - 2³ = 2191823 is a prime.

It is a super-2 number, since 2×2191831² = 9608246265122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2191796 and 2191805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191811) 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, 5155 + ... + 5563.

It is an arithmetic number, because the mean of its divisors is an integer number (287820).

2^2191831 is an apocalyptic number.

2191831 is a deficient number, since it is larger than the sum of its proper divisors (110729).

2191831 is a wasteful number, since it uses less digits than its factorization.

2191831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665.

The product of its digits is 432, while the sum is 25.

The square root of 2191831 is about 1480.4833670123. The cubic root of 2191831 is about 129.8979672761.

The spelling of 2191831 in words is "two million, one hundred ninety-one thousand, eight hundred thirty-one".