121556215 has 16 divisors (see below), whose sum is σ = 160030080. Its totient is φ = 87903520.

The previous prime is 121556213. The next prime is 121556221. The reversal of 121556215 is 512655121.

It is not a de Polignac number, because 121556215 - 2¹ = 121556213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121556213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3672 + ... + 16018.

It is an arithmetic number, because the mean of its divisors is an integer number (10001880).

Almost surely, 2^121556215 is an apocalyptic number.

121556215 is a deficient number, since it is larger than the sum of its proper divisors (38473865).

121556215 is a wasteful number, since it uses less digits than its factorization.

121556215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12542.

The product of its digits is 3000, while the sum is 28.

The square root of 121556215 is about 11025.2535118246. The cubic root of 121556215 is about 495.3654614991.

It can be divided in two parts, 121556 and 215, that added together give a triangular number (121771 = T₄₉₃).

The spelling of 121556215 in words is "one hundred twenty-one million, five hundred fifty-six thousand, two hundred fifteen".