129551 has 4 divisors (see below), whose sum is σ = 130272. Its totient is φ = 128832.

The previous prime is 129539. The next prime is 129553. The reversal of 129551 is 155921.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 129551 - 2¹⁴ = 113167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170 + ... + 536.

It is an arithmetic number, because the mean of its divisors is an integer number (32568).

2¹²⁹⁵⁵¹ is an apocalyptic number.

129551 is a deficient number, since it is larger than the sum of its proper divisors (721).

129551 is an equidigital number, since it uses as much as digits as its factorization.

129551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720.

The product of its digits is 450, while the sum is 23.

The square root of 129551 is about 359.9319380105. The cubic root of 129551 is about 50.5995813054.

The spelling of 129551 in words is "one hundred twenty-nine thousand, five hundred fifty-one".