128997907 has 4 divisors (see below), whose sum is σ = 130275216. Its totient is φ = 127720600.

The previous prime is 128997899. The next prime is 128997917. The reversal of 128997907 is 709799821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 709799821 = 101 ⋅7027721.

It is a cyclic number.

It is not a de Polignac number, because 128997907 - 2³ = 128997899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128997917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 638503 + ... + 638704.

It is an arithmetic number, because the mean of its divisors is an integer number (32568804).

Almost surely, 2^128997907 is an apocalyptic number.

128997907 is a deficient number, since it is larger than the sum of its proper divisors (1277309).

128997907 is a wasteful number, since it uses less digits than its factorization.

128997907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277308.

The product of its (nonzero) digits is 571536, while the sum is 52.

The square root of 128997907 is about 11357.7245520395. The cubic root of 128997907 is about 505.2747020299.

The spelling of 128997907 in words is "one hundred twenty-eight million, nine hundred ninety-seven thousand, nine hundred seven".