2018991 has 8 divisors (see below), whose sum is σ = 2899120. Its totient is φ = 1242432.

The previous prime is 2018987. The next prime is 2018993. The reversal of 2018991 is 1998102.

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

It is not a de Polignac number, because 2018991 - 2² = 2018987 is a prime.

It is an Ulam 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 (2018993) 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, 25846 + ... + 25923.

It is an arithmetic number, because the mean of its divisors is an integer number (362390).

2^2018991 is an apocalyptic number.

2018991 is a deficient number, since it is larger than the sum of its proper divisors (880129).

2018991 is a wasteful number, since it uses less digits than its factorization.

2018991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51785.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 2018991 is about 1420.9120310561. The cubic root of 2018991 is about 126.3896353930.

The spelling of 2018991 in words is "two million, eighteen thousand, nine hundred ninety-one".