2189581 has 4 divisors (see below), whose sum is σ = 2212252. Its totient is φ = 2166912.

The previous prime is 2189573. The next prime is 2189599. The reversal of 2189581 is 1859812.

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 476100 + 1713481 = 690^2 + 1309^2 .

It is a cyclic number.

It is not a de Polignac number, because 2189581 - 2³ = 2189573 is a prime.

It is a super-2 number, since 2×2189581² = 9588529911122, 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 (2189521) 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, 11190 + ... + 11383.

It is an arithmetic number, because the mean of its divisors is an integer number (553063).

2^2189581 is an apocalyptic number.

It is an amenable number.

2189581 is a deficient number, since it is larger than the sum of its proper divisors (22671).

2189581 is an equidigital number, since it uses as much as digits as its factorization.

2189581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22670.

The product of its digits is 5760, while the sum is 34.

The square root of 2189581 is about 1479.7232849422. The cubic root of 2189581 is about 129.8535036150.

The spelling of 2189581 in words is "two million, one hundred eighty-nine thousand, five hundred eighty-one".