121656556 has 48 divisors (see below), whose sum is σ = 259725312. Its totient is φ = 48672000.

The previous prime is 121656551. The next prime is 121656581. The reversal of 121656556 is 655656121.

It is a super-2 number, since 2×121656556² = 29600635235562272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (121656551) 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, 61381 + ... + 63331.

It is an arithmetic number, because the mean of its divisors is an integer number (5410944).

Almost surely, 2^121656556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121656556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129862656).

121656556 is an abundant number, since it is smaller than the sum of its proper divisors (138068756).

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

121656556 is a wasteful number, since it uses less digits than its factorization.

121656556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110 (or 2108 counting only the distinct ones).

The product of its digits is 54000, while the sum is 37.

The square root of 121656556 is about 11029.8030807445. The cubic root of 121656556 is about 495.5017271088.

It can be divided in two parts, 12165 and 6556, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 121656556 in words is "one hundred twenty-one million, six hundred fifty-six thousand, five hundred fifty-six".