129163891 has 4 divisors (see below), whose sum is σ = 129204712. Its totient is φ = 129123072.

The previous prime is 129163889. The next prime is 129163907. The reversal of 129163891 is 198361921.

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 129163891 - 2¹ = 129163889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129163871) 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, 15225 + ... + 22138.

It is an arithmetic number, because the mean of its divisors is an integer number (32301178).

Almost surely, 2^129163891 is an apocalyptic number.

129163891 is a deficient number, since it is larger than the sum of its proper divisors (40821).

129163891 is an equidigital number, since it uses as much as digits as its factorization.

129163891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40820.

The product of its digits is 23328, while the sum is 40.

The square root of 129163891 is about 11365.0293004462. The cubic root of 129163891 is about 505.4913245899.

It can be divided in two parts, 12916 and 3891, that added together give a 5-th power (16807 = 7⁵).

The spelling of 129163891 in words is "one hundred twenty-nine million, one hundred sixty-three thousand, eight hundred ninety-one".