121644 has 36 divisors (see below), whose sum is σ = 320320. Its totient is φ = 38880.

The previous prime is 121637. The next prime is 121661. The reversal of 121644 is 446121.

121644 = 47² + 48² + ... + 77².

121644 is a `hidden beast` number, since 1 + 21 + 644 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

121644 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 11 ways as a sum of consecutive naturals, for example, 1062 + ... + 1170.

2¹²¹⁶⁴⁴ 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 121644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160160).

121644 is an abundant number, since it is smaller than the sum of its proper divisors (198676).

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

121644 is a wasteful number, since it uses less digits than its factorization.

121644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 145 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 121644 is about 348.7749991040. The cubic root of 121644 is about 49.5484679846.

Adding to 121644 its reverse (446121), we get a palindrome (567765).

The spelling of 121644 in words is "one hundred twenty-one thousand, six hundred forty-four".