128990915 has 4 divisors (see below), whose sum is σ = 154789104. Its totient is φ = 103192728.

The previous prime is 128990903. The next prime is 128990921. The reversal of 128990915 is 519099821.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 128990915 - 2⁴ = 128990899 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12899087 + ... + 12899096.

It is an arithmetic number, because the mean of its divisors is an integer number (38697276).

Almost surely, 2^128990915 is an apocalyptic number.

128990915 is a deficient number, since it is larger than the sum of its proper divisors (25798189).

128990915 is an equidigital number, since it uses as much as digits as its factorization.

128990915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25798188.

The product of its (nonzero) digits is 58320, while the sum is 44.

The square root of 128990915 is about 11357.4167397344. The cubic root of 128990915 is about 505.2655728261.

The spelling of 128990915 in words is "one hundred twenty-eight million, nine hundred ninety thousand, nine hundred fifteen".