129921 has 16 divisors (see below), whose sum is σ = 196608. Its totient is φ = 75600.

The previous prime is 129919. The next prime is 129937.

129921 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 129921 - 2¹ = 129919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 129891 and 129900.

It is not an unprimeable number, because it can be changed into a prime (129901) 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, 960 + ... + 1086.

It is an arithmetic number, because the mean of its divisors is an integer number (12288).

It is a Poulet number, since it divides 2¹²⁹⁹²⁰-1.

2¹²⁹⁹²¹ is an apocalyptic number.

129921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129921 is a deficient number, since it is larger than the sum of its proper divisors (66687).

129921 is a wasteful number, since it uses less digits than its factorization.

129921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172.

The product of its digits is 324, while the sum is 24.

The square root of 129921 is about 360.4455576089. The cubic root of 129921 is about 50.6477066254.

The spelling of 129921 in words is "one hundred twenty-nine thousand, nine hundred twenty-one".