129998989 has 2 divisors, whose sum is σ = 129998990. Its totient is φ = 129998988.

The previous prime is 129998963. The next prime is 129999011. The reversal of 129998989 is 989899921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105575625 + 24423364 = 10275^2 + 4942^2 .

It is a cyclic number.

It is not a de Polignac number, because 129998989 - 2¹³ = 129990797 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 129998989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129998189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64999494 + 64999495.

It is an arithmetic number, because the mean of its divisors is an integer number (64999495).

Almost surely, 2^129998989 is an apocalyptic number.

It is an amenable number.

129998989 is a deficient number, since it is larger than the sum of its proper divisors (1).

129998989 is an equidigital number, since it uses as much as digits as its factorization.

129998989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7558272, while the sum is 64.

The square root of 129998989 is about 11401.7099156223. The cubic root of 129998989 is about 506.5783886962.

It can be divided in two parts, 1299989 and 89, that added together give a triangular number (1300078 = T₁₆₁₂).

The spelling of 129998989 in words is "one hundred twenty-nine million, nine hundred ninety-eight thousand, nine hundred eighty-nine".