128646778 has 16 divisors (see below), whose sum is σ = 208010880. Its totient is φ = 59319216.

The previous prime is 128646761. The next prime is 128646799. The reversal of 128646778 is 877646821.

It is a happy number.

It is a super-3 number, since 3×128646778³ (a number of 25 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40243 + ... + 43321.

It is an arithmetic number, because the mean of its divisors is an integer number (13000680).

Almost surely, 2^128646778 is an apocalyptic number.

128646778 is a deficient number, since it is larger than the sum of its proper divisors (79364102).

128646778 is a wasteful number, since it uses less digits than its factorization.

128646778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4701.

The product of its digits is 903168, while the sum is 49.

The square root of 128646778 is about 11342.2563011069. The cubic root of 128646778 is about 504.8158371710.

The spelling of 128646778 in words is "one hundred twenty-eight million, six hundred forty-six thousand, seven hundred seventy-eight".