121556220 has 48 divisors (see below), whose sum is σ = 342171648. Its totient is φ = 32242240.

The previous prime is 121556213. The next prime is 121556221. The reversal of 121556220 is 22655121.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121556221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6157 + ... + 16763.

It is an arithmetic number, because the mean of its divisors is an integer number (7128576).

Almost surely, 2^121556220 is an apocalyptic number.

121556220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121556220 is an abundant number, since it is smaller than the sum of its proper divisors (220615428).

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

121556220 is a wasteful number, since it uses less digits than its factorization.

121556220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10810 (or 10808 counting only the distinct ones).

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

The square root of 121556220 is about 11025.2537385767. The cubic root of 121556220 is about 495.3654682911.

The spelling of 121556220 in words is "one hundred twenty-one million, five hundred fifty-six thousand, two hundred twenty".