128512778 has 32 divisors (see below), whose sum is σ = 202704768. Its totient is φ = 61056000.

The previous prime is 128512759. The next prime is 128512823. The reversal of 128512778 is 877215821.

It is a Harshad number since it is a multiple of its sum of digits (41).

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, 851003 + ... + 851153.

It is an arithmetic number, because the mean of its divisors is an integer number (6334524).

Almost surely, 2^128512778 is an apocalyptic number.

128512778 is a deficient number, since it is larger than the sum of its proper divisors (74191990).

128512778 is a wasteful number, since it uses less digits than its factorization.

128512778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398.

The product of its digits is 62720, while the sum is 41.

The square root of 128512778 is about 11336.3476481625. The cubic root of 128512778 is about 504.6405022382.

The spelling of 128512778 in words is "one hundred twenty-eight million, five hundred twelve thousand, seven hundred seventy-eight".