12121556 has 6 divisors (see below), whose sum is σ = 21212730. Its totient is φ = 6060776.

The previous prime is 12121547. The next prime is 12121579. The reversal of 12121556 is 65512121.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 12040900 + 80656 = 3470^2 + 284^2 .

It is a super-2 number, since 2×12121556² = 293864239722272, 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 as a sum of consecutive naturals, namely, 1515191 + ... + 1515198.

It is an arithmetic number, because the mean of its divisors is an integer number (3535455).

Almost surely, 2^12121556 is an apocalyptic number.

It is an amenable number.

12121556 is a deficient number, since it is larger than the sum of its proper divisors (9091174).

12121556 is a wasteful number, since it uses less digits than its factorization.

12121556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3030393 (or 3030391 counting only the distinct ones).

The product of its digits is 600, while the sum is 23.

The square root of 12121556 is about 3481.6025045947. The cubic root of 12121556 is about 229.7132911418.

Adding to 12121556 its reverse (65512121), we get a palindrome (77633677).

The spelling of 12121556 in words is "twelve million, one hundred twenty-one thousand, five hundred fifty-six".