129387813 has 4 divisors (see below), whose sum is σ = 172517088. Its totient is φ = 86258540.

The previous prime is 129387809. The next prime is 129387871. The reversal of 129387813 is 318783921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 129387813 - 2² = 129387809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129387803) 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, 21564633 + ... + 21564638.

It is an arithmetic number, because the mean of its divisors is an integer number (43129272).

Almost surely, 2^129387813 is an apocalyptic number.

It is an amenable number.

129387813 is a deficient number, since it is larger than the sum of its proper divisors (43129275).

129387813 is an equidigital number, since it uses as much as digits as its factorization.

129387813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43129274.

The product of its digits is 72576, while the sum is 42.

The square root of 129387813 is about 11374.8763949328. The cubic root of 129387813 is about 505.7832670730.

The spelling of 129387813 in words is "one hundred twenty-nine million, three hundred eighty-seven thousand, eight hundred thirteen".