2261581 has 4 divisors (see below), whose sum is σ = 2584672. Its totient is φ = 1938492.

The previous prime is 2261573. The next prime is 2261587. The reversal of 2261581 is 1851622.

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 a cyclic number.

It is not a de Polignac number, because 2261581 - 2³ = 2261573 is a prime.

It is a super-2 number, since 2×2261581² = 10229497239122, which contains 22 as substring.

It is an Ulam 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 (2261587) 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, 161535 + ... + 161548.

It is an arithmetic number, because the mean of its divisors is an integer number (646168).

2^2261581 is an apocalyptic number.

It is an amenable number.

2261581 is a deficient number, since it is larger than the sum of its proper divisors (323091).

2261581 is an equidigital number, since it uses as much as digits as its factorization.

2261581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323090.

The product of its digits is 960, while the sum is 25.

The square root of 2261581 is about 1503.8553786851. The cubic root of 2261581 is about 131.2615058696.

The spelling of 2261581 in words is "two million, two hundred sixty-one thousand, five hundred eighty-one".