12221556 has 24 divisors (see below), whose sum is σ = 29757504. Its totient is φ = 3896640.

The previous prime is 12221543. The next prime is 12221593. The reversal of 12221556 is 65512221.

It is a happy number.

It is a super-2 number, since 2×12221556² = 298732862122272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21865 + ... + 22416.

It is an arithmetic number, because the mean of its divisors is an integer number (1239896).

Almost surely, 2^12221556 is an apocalyptic number.

It is an amenable number.

12221556 is an abundant number, since it is smaller than the sum of its proper divisors (17535948).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12221556 is a wasteful number, since it uses less digits than its factorization.

12221556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44311 (or 44309 counting only the distinct ones).

The product of its digits is 1200, while the sum is 24.

The square root of 12221556 is about 3495.9342099073. The cubic root of 12221556 is about 230.3432555811.

Adding to 12221556 its reverse (65512221), we get a palindrome (77733777).

The spelling of 12221556 in words is "twelve million, two hundred twenty-one thousand, five hundred fifty-six".