2549581 has 4 divisors (see below), whose sum is σ = 2555100. Its totient is φ = 2544064.

The previous prime is 2549579. The next prime is 2549587. The reversal of 2549581 is 1859452.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1664100 + 885481 = 1290^2 + 941^2 .

It is a cyclic number.

It is not a de Polignac number, because 2549581 - 2¹ = 2549579 is a prime.

It is a super-2 number, since 2×2549581² = 13000726551122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2549587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1996 + ... + 3013.

It is an arithmetic number, because the mean of its divisors is an integer number (638775).

2^2549581 is an apocalyptic number.

It is an amenable number.

2549581 is a deficient number, since it is larger than the sum of its proper divisors (5519).

2549581 is an equidigital number, since it uses as much as digits as its factorization.

2549581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5518.

The product of its digits is 14400, while the sum is 34.

The square root of 2549581 is about 1596.7407428885. The cubic root of 2549581 is about 136.6122375631.

It can be divided in two parts, 25 and 49581, that multiplied together give a triangular number (1239525 = T₁₅₇₄).

The spelling of 2549581 in words is "two million, five hundred forty-nine thousand, five hundred eighty-one".