129424921 has 4 divisors (see below), whose sum is σ = 129465700. Its totient is φ = 129384144.

The previous prime is 129424913. The next prime is 129424931.

It is a happy number.

129424921 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26625600 + 102799321 = 5160^2 + 10139^2 .

It is a cyclic number.

It is not a de Polignac number, because 129424921 - 2³ = 129424913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129424931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15186 + ... + 22123.

It is an arithmetic number, because the mean of its divisors is an integer number (32366425).

Almost surely, 2^129424921 is an apocalyptic number.

It is an amenable number.

129424921 is a deficient number, since it is larger than the sum of its proper divisors (40779).

129424921 is an equidigital number, since it uses as much as digits as its factorization.

129424921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40778.

The product of its digits is 10368, while the sum is 34.

The square root of 129424921 is about 11376.5074166020. The cubic root of 129424921 is about 505.8316147782.

The spelling of 129424921 in words is "one hundred twenty-nine million, four hundred twenty-four thousand, nine hundred twenty-one".