129521 has 4 divisors (see below), whose sum is σ = 148032. Its totient is φ = 111012.

The previous prime is 129517. The next prime is 129527. The reversal of 129521 is 125921.

129521 is nontrivially palindromic in base 16.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 129521 - 2² = 129517 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 129493 and 129502.

It is not an unprimeable number, because it can be changed into a prime (129527) 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, 9245 + ... + 9258.

It is an arithmetic number, because the mean of its divisors is an integer number (37008).

2¹²⁹⁵²¹ is an apocalyptic number.

It is an amenable number.

129521 is a deficient number, since it is larger than the sum of its proper divisors (18511).

129521 is an equidigital number, since it uses as much as digits as its factorization.

129521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18510.

The product of its digits is 180, while the sum is 20.

The square root of 129521 is about 359.8902610519. The cubic root of 129521 is about 50.5956752385.

Subtracting from 129521 its reverse (125921), we obtain a square (3600 = 60²).

The spelling of 129521 in words is "one hundred twenty-nine thousand, five hundred twenty-one".