129242721 has 8 divisors (see below), whose sum is σ = 182460384. Its totient is φ = 81093440.

The previous prime is 129242719. The next prime is 129242723. The reversal of 129242721 is 127242921.

It is an interprime number because it is at equal distance from previous prime (129242719) and next prime (129242723).

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

It is a cyclic number.

It is not a de Polignac number, because 129242721 - 2¹ = 129242719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129242723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1267035 + ... + 1267136.

It is an arithmetic number, because the mean of its divisors is an integer number (22807548).

Almost surely, 2^129242721 is an apocalyptic number.

It is an amenable number.

129242721 is a deficient number, since it is larger than the sum of its proper divisors (53217663).

129242721 is a wasteful number, since it uses less digits than its factorization.

129242721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2534191.

The product of its digits is 4032, while the sum is 30.

The square root of 129242721 is about 11368.4968663408. The cubic root of 129242721 is about 505.5941391279.

The spelling of 129242721 in words is "one hundred twenty-nine million, two hundred forty-two thousand, seven hundred twenty-one".