128533666 has 4 divisors (see below), whose sum is σ = 192800502. Its totient is φ = 64266832.

The previous prime is 128533621. The next prime is 128533679. The reversal of 128533666 is 666335821.

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., 108472225 + 20061441 = 10415^2 + 4479^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32133415 + ... + 32133418.

Almost surely, 2^128533666 is an apocalyptic number.

128533666 is a deficient number, since it is larger than the sum of its proper divisors (64266836).

128533666 is an equidigital number, since it uses as much as digits as its factorization.

128533666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64266835.

The product of its digits is 155520, while the sum is 40.

The square root of 128533666 is about 11337.2688951087. The cubic root of 128533666 is about 504.6678415683.

The spelling of 128533666 in words is "one hundred twenty-eight million, five hundred thirty-three thousand, six hundred sixty-six".