128609786 has 4 divisors (see below), whose sum is σ = 192914682. Its totient is φ = 64304892.

The previous prime is 128609779. The next prime is 128609791. The reversal of 128609786 is 687906821.

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

It can be written as a sum of positive squares in only one way, i.e., 77986561 + 50623225 = 8831^2 + 7115^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 128609786.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32152445 + ... + 32152448.

Almost surely, 2^128609786 is an apocalyptic number.

128609786 is a deficient number, since it is larger than the sum of its proper divisors (64304896).

128609786 is an equidigital number, since it uses as much as digits as its factorization.

128609786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64304895.

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 128609786 is about 11340.6254677597. The cubic root of 128609786 is about 504.7674464329.

The spelling of 128609786 in words is "one hundred twenty-eight million, six hundred nine thousand, seven hundred eighty-six".