2571991 has 4 divisors (see below), whose sum is σ = 2587032. Its totient is φ = 2556952.

The previous prime is 2571979. The next prime is 2572001. The reversal of 2571991 is 1991752.

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 2571991 - 2¹¹ = 2569943 is a prime.

It is a Duffinian number.

2571991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2571911) 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, 7261 + ... + 7606.

It is an arithmetic number, because the mean of its divisors is an integer number (646758).

2^2571991 is an apocalyptic number.

2571991 is a deficient number, since it is larger than the sum of its proper divisors (15041).

2571991 is a wasteful number, since it uses less digits than its factorization.

2571991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15040.

The product of its digits is 5670, while the sum is 34.

The square root of 2571991 is about 1603.7428098046. The cubic root of 2571991 is about 137.0113298034.

The spelling of 2571991 in words is "two million, five hundred seventy-one thousand, nine hundred ninety-one".