128115778 has 16 divisors (see below), whose sum is σ = 219798720. Its totient is φ = 54863856.

The previous prime is 128115769. The next prime is 128115797. The reversal of 128115778 is 877511821.

It is a self number, because there is not a number n which added to its sum of digits gives 128115778.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20625 + ... + 26107.

It is an arithmetic number, because the mean of its divisors is an integer number (13737420).

Almost surely, 2^128115778 is an apocalyptic number.

128115778 is a deficient number, since it is larger than the sum of its proper divisors (91682942).

128115778 is a wasteful number, since it uses less digits than its factorization.

128115778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7161.

The product of its digits is 31360, while the sum is 40.

The square root of 128115778 is about 11318.8240555280. The cubic root of 128115778 is about 504.1203232710.

The spelling of 128115778 in words is "one hundred twenty-eight million, one hundred fifteen thousand, seven hundred seventy-eight".