12213561 has 24 divisors (see below), whose sum is σ = 17694880. Its totient is φ = 7471872.

The previous prime is 12213541. The next prime is 12213571. The reversal of 12213561 is 16531221.

It is not a de Polignac number, because 12213561 - 2⁹ = 12213049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12213511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 125865 + ... + 125961.

Almost surely, 2^12213561 is an apocalyptic number.

It is an amenable number.

12213561 is a deficient number, since it is larger than the sum of its proper divisors (5481319).

12213561 is an equidigital number, since it uses as much as digits as its factorization.

12213561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 166 counting only the distinct ones).

The product of its digits is 360, while the sum is 21.

The square root of 12213561 is about 3494.7905516640. The cubic root of 12213561 is about 230.2930165868.

Adding to 12213561 its reverse (16531221), we get a palindrome (28744782).

The spelling of 12213561 in words is "twelve million, two hundred thirteen thousand, five hundred sixty-one".