121428 has 18 divisors (see below), whose sum is σ = 307034. Its totient is φ = 40464.

The previous prime is 121421. The next prime is 121439. The reversal of 121428 is 824121.

It can be written as a sum of positive squares in only one way, i.e., 121104 + 324 = 348^2 + 18^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 121428.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 121428.

It is not an unprimeable number, because it can be changed into a prime (121421) by changing a digit.

121428 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 5 ways as a sum of consecutive naturals, for example, 1651 + ... + 1722.

2¹²¹⁴²⁸ is an apocalyptic number.

121428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

121428 is an abundant number, since it is smaller than the sum of its proper divisors (185606).

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

121428 is a wasteful number, since it uses less digits than its factorization.

121428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3383 (or 3378 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 121428 is about 348.4652062976. The cubic root of 121428 is about 49.5191233121.

Adding to 121428 its reverse (824121), we get a palindrome (945549).

The spelling of 121428 in words is "one hundred twenty-one thousand, four hundred twenty-eight".