129811387 has 4 divisors (see below), whose sum is σ = 132011640. Its totient is φ = 127611136.

The previous prime is 129811373. The next prime is 129811393. The reversal of 129811387 is 783118921.

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

It is a cyclic number.

It is not a de Polignac number, because 129811387 - 2⁷ = 129811259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129811987) 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, 1100038 + ... + 1100155.

It is an arithmetic number, because the mean of its divisors is an integer number (33002910).

Almost surely, 2^129811387 is an apocalyptic number.

129811387 is a deficient number, since it is larger than the sum of its proper divisors (2200253).

129811387 is an equidigital number, since it uses as much as digits as its factorization.

129811387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200252.

The product of its digits is 24192, while the sum is 40.

The square root of 129811387 is about 11393.4800214860. The cubic root of 129811387 is about 506.3345896958.

The spelling of 129811387 in words is "one hundred twenty-nine million, eight hundred eleven thousand, three hundred eighty-seven".