128816686 has 4 divisors (see below), whose sum is σ = 193225032. Its totient is φ = 64408342.

The previous prime is 128816671. The next prime is 128816693. The reversal of 128816686 is 686618821.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32204170 + ... + 32204173.

It is an arithmetic number, because the mean of its divisors is an integer number (48306258).

Almost surely, 2^128816686 is an apocalyptic number.

128816686 is a deficient number, since it is larger than the sum of its proper divisors (64408346).

128816686 is an equidigital number, since it uses as much as digits as its factorization.

128816686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64408345.

The product of its digits is 221184, while the sum is 46.

The square root of 128816686 is about 11349.7438737621. The cubic root of 128816686 is about 505.0379816546.

The spelling of 128816686 in words is "one hundred twenty-eight million, eight hundred sixteen thousand, six hundred eighty-six".