129128013 has 24 divisors (see below), whose sum is σ = 221061568. Its totient is φ = 73786464.

The previous prime is 129127987. The next prime is 129128057. The reversal of 129128013 is 310821921.

It is not a de Polignac number, because 129128013 - 2⁹ = 129127501 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129128063) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36256 + ... + 39657.

Almost surely, 2^129128013 is an apocalyptic number.

It is an amenable number.

129128013 is a deficient number, since it is larger than the sum of its proper divisors (91933555).

129128013 is an frugal number, since it uses more digits than its factorization.

129128013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75935 (or 75923 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 129128013 is about 11363.4507523023. The cubic root of 129128013 is about 505.4445166235. Note that the first 3 decimals are identical.

Adding to 129128013 its reverse (310821921), we get a palindrome (439949934).

The spelling of 129128013 in words is "one hundred twenty-nine million, one hundred twenty-eight thousand, thirteen".