129889961 has 4 divisors (see below), whose sum is σ = 129916932. Its totient is φ = 129862992.

The previous prime is 129889933. The next prime is 129890011. The reversal of 129889961 is 169988921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 169988921 = 1259 ⋅135019.

It can be written as a sum of positive squares in 2 ways, for example, as 122766400 + 7123561 = 11080^2 + 2669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129889961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129889931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4070 + ... + 16623.

It is an arithmetic number, because the mean of its divisors is an integer number (32479233).

Almost surely, 2^129889961 is an apocalyptic number.

It is an amenable number.

129889961 is a deficient number, since it is larger than the sum of its proper divisors (26971).

129889961 is an equidigital number, since it uses as much as digits as its factorization.

129889961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26970.

The product of its digits is 559872, while the sum is 53.

The square root of 129889961 is about 11396.9277000427. The cubic root of 129889961 is about 506.4367294503.

The spelling of 129889961 in words is "one hundred twenty-nine million, eight hundred eighty-nine thousand, nine hundred sixty-one".