128638633 has 4 divisors (see below), whose sum is σ = 128825488. Its totient is φ = 128451780.

The previous prime is 128638621. The next prime is 128638637. The reversal of 128638633 is 336836821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 336836821 = 743 ⋅453347.

It is a cyclic number.

It is not a de Polignac number, because 128638633 - 2⁹ = 128638121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128638637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92391 + ... + 93772.

It is an arithmetic number, because the mean of its divisors is an integer number (32206372).

Almost surely, 2^128638633 is an apocalyptic number.

It is an amenable number.

128638633 is a deficient number, since it is larger than the sum of its proper divisors (186855).

128638633 is an equidigital number, since it uses as much as digits as its factorization.

128638633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186854.

The product of its digits is 124416, while the sum is 40.

The square root of 128638633 is about 11341.8972398801. The cubic root of 128638633 is about 504.8051831620.

The spelling of 128638633 in words is "one hundred twenty-eight million, six hundred thirty-eight thousand, six hundred thirty-three".