12209581 has 4 divisors (see below), whose sum is σ = 12226972. Its totient is φ = 12192192.

The previous prime is 12209579. The next prime is 12209591. The reversal of 12209581 is 18590221.

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 12075625 + 133956 = 3475^2 + 366^2 .

It is a cyclic number.

It is not a de Polignac number, because 12209581 - 2¹ = 12209579 is a prime.

It is a super-2 number, since 2×12209581² = 298147736391122, 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 (12209501) 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, 7596 + ... + 9061.

It is an arithmetic number, because the mean of its divisors is an integer number (3056743).

Almost surely, 2^12209581 is an apocalyptic number.

It is an amenable number.

12209581 is a deficient number, since it is larger than the sum of its proper divisors (17391).

12209581 is an equidigital number, since it uses as much as digits as its factorization.

12209581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17390.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 12209581 is about 3494.2210863081. The cubic root of 12209581 is about 230.2679988822.

It can be divided in two parts, 1220 and 9581, that added together give a palindrome (10801).

The spelling of 12209581 in words is "twelve million, two hundred nine thousand, five hundred eighty-one".