1221556 has 12 divisors (see below), whose sum is σ = 2443168. Its totient is φ = 523512.

The previous prime is 1221551. The next prime is 1221557. The reversal of 1221556 is 6551221.

1221556 = 214² + 215² + ... + 237².

1221556 is an admirable number.

It is a super-2 number, since 2×1221556² = 2984398122272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221551) 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, 21786 + ... + 21841.

2^1221556 is an apocalyptic number.

It is an amenable number.

1221556 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1221556 is a wasteful number, since it uses less digits than its factorization.

1221556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43638 (or 43636 counting only the distinct ones).

The product of its digits is 600, while the sum is 22.

The square root of 1221556 is about 1105.2402453765. The cubic root of 1221556 is about 106.8983808268.

Adding to 1221556 its reverse (6551221), we get a palindrome (7772777).

It can be divided in two parts, 1221 and 556, that multiplied together give a palindrome (678876).

The spelling of 1221556 in words is "one million, two hundred twenty-one thousand, five hundred fifty-six".