12221557 has 4 divisors (see below), whose sum is σ = 12643020. Its totient is φ = 11800096.

The previous prime is 12221543. The next prime is 12221593. The reversal of 12221557 is 75512221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75512221 = 47 ⋅1606643.

It can be written as a sum of positive squares in 2 ways, for example, as 5044516 + 7177041 = 2246^2 + 2679^2 .

It is a cyclic number.

It is not a de Polignac number, because 12221557 - 2¹⁵ = 12188789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12221527) 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, 210688 + ... + 210745.

It is an arithmetic number, because the mean of its divisors is an integer number (3160755).

Almost surely, 2^12221557 is an apocalyptic number.

It is an amenable number.

12221557 is a deficient number, since it is larger than the sum of its proper divisors (421463).

12221557 is an equidigital number, since it uses as much as digits as its factorization.

12221557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421462.

The product of its digits is 1400, while the sum is 25.

The square root of 12221557 is about 3495.9343529306. The cubic root of 12221557 is about 230.3432618636.

Adding to 12221557 its reverse (75512221), we get a palindrome (87733778).

The spelling of 12221557 in words is "twelve million, two hundred twenty-one thousand, five hundred fifty-seven".