121728 has 32 divisors (see below), whose sum is σ = 324360. Its totient is φ = 40448.

The previous prime is 121727. The next prime is 121763. The reversal of 121728 is 827121.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 226 + ... + 542.

2¹²¹⁷²⁸ 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 121728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162180).

121728 is an abundant number, since it is smaller than the sum of its proper divisors (202632).

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

121728 is an equidigital number, since it uses as much as digits as its factorization.

121728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 322 counting only the distinct ones).

The product of its digits is 224, while the sum is 21.

The square root of 121728 is about 348.8953997977. The cubic root of 121728 is about 49.5598704203.

Adding to 121728 its reverse (827121), we get a palindrome (948849).

It can be divided in two parts, 121 and 728, that multiplied together give a palindrome (88088).

The spelling of 121728 in words is "one hundred twenty-one thousand, seven hundred twenty-eight".