6631891 has 4 divisors (see below), whose sum is σ = 7579312. Its totient is φ = 5684472.

The previous prime is 6631883. The next prime is 6631901. The reversal of 6631891 is 1981366.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6631891 - 2³ = 6631883 is a prime.

It is a Duffinian number.

6631891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6631871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 473700 + ... + 473713.

It is an arithmetic number, because the mean of its divisors is an integer number (1894828).

Almost surely, 2^6631891 is an apocalyptic number.

6631891 is a deficient number, since it is larger than the sum of its proper divisors (947421).

6631891 is an equidigital number, since it uses as much as digits as its factorization.

6631891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 947420.

The product of its digits is 7776, while the sum is 34.

The square root of 6631891 is about 2575.2458135098. The cubic root of 6631891 is about 187.8793835493.

The spelling of 6631891 in words is "six million, six hundred thirty-one thousand, eight hundred ninety-one".