2191887 has 8 divisors (see below), whose sum is σ = 3247280. Its totient is φ = 1461240.

The previous prime is 2191883. The next prime is 2191949. The reversal of 2191887 is 7881912.

It is not a de Polignac number, because 2191887 - 2² = 2191883 is a prime.

It is a Duffinian number.

2191887 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191883) 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, 40564 + ... + 40617.

It is an arithmetic number, because the mean of its divisors is an integer number (405910).

2^2191887 is an apocalyptic number.

2191887 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

2191887 is a deficient number, since it is larger than the sum of its proper divisors (1055393).

2191887 is an equidigital number, since it uses as much as digits as its factorization.

2191887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81190 (or 81184 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 2191887 is about 1480.5022796335. The cubic root of 2191887 is about 129.8990735390.

The spelling of 2191887 in words is "two million, one hundred ninety-one thousand, eight hundred eighty-seven".