121656 has 32 divisors (see below), whose sum is σ = 314640. Its totient is φ = 39168.

The previous prime is 121637. The next prime is 121661. The reversal of 121656 is 656121.

It is a happy number.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is an unprimeable number.

121656 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 820 + ... + 956.

2¹²¹⁶⁵⁶ 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 121656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157320).

121656 is an abundant number, since it is smaller than the sum of its proper divisors (192984).

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

121656 is a wasteful number, since it uses less digits than its factorization.

121656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 179 counting only the distinct ones).

The product of its digits is 360, while the sum is 21.

The square root of 121656 is about 348.7922017477. The cubic root of 121656 is about 49.5500972253.

Adding to 121656 its reverse (656121), we get a palindrome (777777).

It can be divided in two parts, 121 and 656, that added together give a palindrome (777).

The spelling of 121656 in words is "one hundred twenty-one thousand, six hundred fifty-six".