2191631 has 12 divisors (see below), whose sum is σ = 2496312. Its totient is φ = 1912464.

The previous prime is 2191627. The next prime is 2191633. The reversal of 2191631 is 1361912.

It is a happy number.

It is not a de Polignac number, because 2191631 - 2² = 2191627 is a prime.

It is a super-2 number, since 2×2191631² = 9606492880322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2191597 and 2191606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4460 + ... + 4926.

It is an arithmetic number, because the mean of its divisors is an integer number (208026).

2^2191631 is an apocalyptic number.

2191631 is a deficient number, since it is larger than the sum of its proper divisors (304681).

2191631 is a wasteful number, since it uses less digits than its factorization.

2191631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518 (or 499 counting only the distinct ones).

The product of its digits is 324, while the sum is 23.

The square root of 2191631 is about 1480.4158199641. The cubic root of 2191631 is about 129.8940161832.

The spelling of 2191631 in words is "two million, one hundred ninety-one thousand, six hundred thirty-one".