2045991 has 4 divisors (see below), whose sum is σ = 2727992. Its totient is φ = 1363992.

The previous prime is 2045987. The next prime is 2045999. The reversal of 2045991 is 1995402.

It is a happy number.

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

It is not a de Polignac number, because 2045991 - 2² = 2045987 is a prime.

It is an Ulam number.

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 (2045999) 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, 340996 + ... + 341001.

It is an arithmetic number, because the mean of its divisors is an integer number (681998).

2^2045991 is an apocalyptic number.

2045991 is a deficient number, since it is larger than the sum of its proper divisors (682001).

2045991 is an equidigital number, since it uses as much as digits as its factorization.

2045991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682000.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 2045991 is about 1430.3814176645. The cubic root of 2045991 is about 126.9505459795.

The spelling of 2045991 in words is "two million, forty-five thousand, nine hundred ninety-one".