128991408 has 80 divisors (see below), whose sum is σ = 410140416. Its totient is φ = 34018560.

The previous prime is 128991367. The next prime is 128991413. The reversal of 128991408 is 804199821.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 128991408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10398 + ... + 19133.

Almost surely, 2^128991408 is an apocalyptic number.

It is an amenable number.

128991408 is an abundant number, since it is smaller than the sum of its proper divisors (281149008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128991408 is a wasteful number, since it uses less digits than its factorization.

128991408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29562 (or 29556 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 42.

The square root of 128991408 is about 11357.4384435928. The cubic root of 128991408 is about 505.2662165294.

The spelling of 128991408 in words is "one hundred twenty-eight million, nine hundred ninety-one thousand, four hundred eight".