129491889 has 4 divisors (see below), whose sum is σ = 172655856. Its totient is φ = 86327924.

The previous prime is 129491849. The next prime is 129491893. The reversal of 129491889 is 988194921.

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 129491889 - 2¹⁷ = 129360817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129491849) 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, 21581979 + ... + 21581984.

It is an arithmetic number, because the mean of its divisors is an integer number (43163964).

Almost surely, 2^129491889 is an apocalyptic number.

It is an amenable number.

129491889 is a deficient number, since it is larger than the sum of its proper divisors (43163967).

129491889 is an equidigital number, since it uses as much as digits as its factorization.

129491889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43163966.

The product of its digits is 373248, while the sum is 51.

The square root of 129491889 is about 11379.4502942805. The cubic root of 129491889 is about 505.9188434470.

The spelling of 129491889 in words is "one hundred twenty-nine million, four hundred ninety-one thousand, eight hundred eighty-nine".