129021 has 8 divisors (see below), whose sum is σ = 178080. Its totient is φ = 82992.

The previous prime is 129011. The next prime is 129023. The reversal of 129021 is 120921.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 129021 - 2⁹ = 128509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655 + ... + 828.

It is an arithmetic number, because the mean of its divisors is an integer number (22260).

2¹²⁹⁰²¹ is an apocalyptic number.

It is an amenable number.

129021 is a deficient number, since it is larger than the sum of its proper divisors (49059).

129021 is a wasteful number, since it uses less digits than its factorization.

129021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 129021 is about 359.1949331491. The cubic root of 129021 is about 50.5304851389.

Adding to 129021 its reverse (120921), we get a palindrome (249942).

Subtracting from 129021 its reverse (120921), we obtain a square (8100 = 90²).

The spelling of 129021 in words is "one hundred twenty-nine thousand, twenty-one".