2387991 has 4 divisors (see below), whose sum is σ = 3183992. Its totient is φ = 1591992.

The previous prime is 2387971. The next prime is 2388013. The reversal of 2387991 is 1997832.

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

It is not a de Polignac number, because 2387991 - 2⁶ = 2387927 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2387911) 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, 397996 + ... + 398001.

It is an arithmetic number, because the mean of its divisors is an integer number (795998).

2^2387991 is an apocalyptic number.

2387991 is a deficient number, since it is larger than the sum of its proper divisors (796001).

2387991 is an equidigital number, since it uses as much as digits as its factorization.

2387991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796000.

The product of its digits is 27216, while the sum is 39.

The square root of 2387991 is about 1545.3125897371. The cubic root of 2387991 is about 133.6629048374.

The spelling of 2387991 in words is "two million, three hundred eighty-seven thousand, nine hundred ninety-one".