129287987 has 4 divisors (see below), whose sum is σ = 129704016. Its totient is φ = 128871960.

The previous prime is 129287981. The next prime is 129287999. The reversal of 129287987 is 789782921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789782921 = 61 ⋅12947261.

It is a cyclic number.

It is not a de Polignac number, because 129287987 - 2⁶ = 129287923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129287981) 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, 207548 + ... + 208169.

It is an arithmetic number, because the mean of its divisors is an integer number (32426004).

Almost surely, 2^129287987 is an apocalyptic number.

129287987 is a deficient number, since it is larger than the sum of its proper divisors (416029).

129287987 is an equidigital number, since it uses as much as digits as its factorization.

129287987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416028.

The product of its digits is 1016064, while the sum is 53.

The square root of 129287987 is about 11370.4875445163. The cubic root of 129287987 is about 505.6531587069.

The spelling of 129287987 in words is "one hundred twenty-nine million, two hundred eighty-seven thousand, nine hundred eighty-seven".