2681581 has 4 divisors (see below), whose sum is σ = 3064672. Its totient is φ = 2298492.

The previous prime is 2681579. The next prime is 2681611. The reversal of 2681581 is 1851862.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2681581 - 2¹ = 2681579 is a prime.

It is a super-2 number, since 2×2681581² = 14381753319122, 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 (2681521) 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, 191535 + ... + 191548.

It is an arithmetic number, because the mean of its divisors is an integer number (766168).

2^2681581 is an apocalyptic number.

It is an amenable number.

2681581 is a deficient number, since it is larger than the sum of its proper divisors (383091).

2681581 is an equidigital number, since it uses as much as digits as its factorization.

2681581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383090.

The product of its digits is 3840, while the sum is 31.

The square root of 2681581 is about 1637.5533579093. The cubic root of 2681581 is about 138.9302999243.

It can be divided in two parts, 26815 and 81, that added together give a square (26896 = 164²).

The spelling of 2681581 in words is "two million, six hundred eighty-one thousand, five hundred eighty-one".