2547991 has 4 divisors (see below), whose sum is σ = 2571912. Its totient is φ = 2524072.

The previous prime is 2547989. The next prime is 2547997. The reversal of 2547991 is 1997452.

2547991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2547991 - 2¹ = 2547989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2547991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2547997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11800 + ... + 12013.

It is an arithmetic number, because the mean of its divisors is an integer number (642978).

2^2547991 is an apocalyptic number.

2547991 is a deficient number, since it is larger than the sum of its proper divisors (23921).

2547991 is a wasteful number, since it uses less digits than its factorization.

2547991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23920.

The product of its digits is 22680, while the sum is 37.

The square root of 2547991 is about 1596.2427760212. The cubic root of 2547991 is about 136.5838330753.

The spelling of 2547991 in words is "two million, five hundred forty-seven thousand, nine hundred ninety-one".