128878665 has 32 divisors (see below), whose sum is σ = 212236416. Its totient is φ = 66754560.

The previous prime is 128878627. The next prime is 128878693. The reversal of 128878665 is 566878821.

It is not a de Polignac number, because 128878665 - 2⁶ = 128878601 is a prime.

It is an unprimeable 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 in 31 ways as a sum of consecutive naturals, for example, 75097 + ... + 76793.

It is an arithmetic number, because the mean of its divisors is an integer number (6632388).

Almost surely, 2^128878665 is an apocalyptic number.

128878665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128878665 is a deficient number, since it is larger than the sum of its proper divisors (83357751).

128878665 is a wasteful number, since it uses less digits than its factorization.

128878665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1849.

The product of its digits is 1290240, while the sum is 51.

The square root of 128878665 is about 11352.4739594504. The cubic root of 128878665 is about 505.1189668416.

The spelling of 128878665 in words is "one hundred twenty-eight million, eight hundred seventy-eight thousand, six hundred sixty-five".