129724789 has 4 divisors (see below), whose sum is σ = 129756556. Its totient is φ = 129693024.

The previous prime is 129724787. The next prime is 129724813. The reversal of 129724789 is 987427921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 987427921 = 127 ⋅7775023.

It can be written as a sum of positive squares in 2 ways, for example, as 93219025 + 36505764 = 9655^2 + 6042^2 .

It is a cyclic number.

It is not a de Polignac number, because 129724789 - 2¹ = 129724787 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 (129724783) 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, 8664 + ... + 18289.

It is an arithmetic number, because the mean of its divisors is an integer number (32439139).

Almost surely, 2^129724789 is an apocalyptic number.

It is an amenable number.

129724789 is a deficient number, since it is larger than the sum of its proper divisors (31767).

129724789 is an equidigital number, since it uses as much as digits as its factorization.

129724789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31766.

The product of its digits is 508032, while the sum is 49.

The square root of 129724789 is about 11389.6790560577. The cubic root of 129724789 is about 506.2219716434.

The spelling of 129724789 in words is "one hundred twenty-nine million, seven hundred twenty-four thousand, seven hundred eighty-nine".