128998 has 4 divisors (see below), whose sum is σ = 193500. Its totient is φ = 64498.

The previous prime is 128993. The next prime is 129001. The reversal of 128998 is 899821.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128993) by changing a digit.

128998 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 as a sum of consecutive naturals, namely, 32248 + ... + 32251.

It is an arithmetic number, because the mean of its divisors is an integer number (48375).

2¹²⁸⁹⁹⁸ is an apocalyptic number.

128998 is a deficient number, since it is larger than the sum of its proper divisors (64502).

128998 is an equidigital number, since it uses as much as digits as its factorization.

128998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64501.

The product of its digits is 10368, while the sum is 37.

The square root of 128998 is about 359.1629156803. The cubic root of 128998 is about 50.5274823454.

The spelling of 128998 in words is "one hundred twenty-eight thousand, nine hundred ninety-eight".