220121556 has 12 divisors (see below), whose sum is σ = 513616992. Its totient is φ = 73373848.

The previous prime is 220121549. The next prime is 220121563. The reversal of 220121556 is 655121022.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (220121549) and next prime (220121563).

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-3 number, since 3×220121556³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9171720 + ... + 9171743.

It is an arithmetic number, because the mean of its divisors is an integer number (42801416).

Almost surely, 2^220121556 is an apocalyptic number.

It is an amenable number.

220121556 is an abundant number, since it is smaller than the sum of its proper divisors (293495436).

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

220121556 is a wasteful number, since it uses less digits than its factorization.

220121556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18343470 (or 18343468 counting only the distinct ones).

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

The square root of 220121556 is about 14836.4940602556. The cubic root of 220121556 is about 603.7922366278.

Adding to 220121556 its reverse (655121022), we get a palindrome (875242578).

The spelling of 220121556 in words is "two hundred twenty million, one hundred twenty-one thousand, five hundred fifty-six".