128756906 has 4 divisors (see below), whose sum is σ = 193135362. Its totient is φ = 64378452.

The previous prime is 128756899. The next prime is 128756941. The reversal of 128756906 is 609657821.

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., 125641681 + 3115225 = 11209^2 + 1765^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32189225 + ... + 32189228.

Almost surely, 2^128756906 is an apocalyptic number.

128756906 is a deficient number, since it is larger than the sum of its proper divisors (64378456).

128756906 is an equidigital number, since it uses as much as digits as its factorization.

128756906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64378455.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 128756906 is about 11347.1100285491. The cubic root of 128756906 is about 504.9598451881.

The spelling of 128756906 in words is "one hundred twenty-eight million, seven hundred fifty-six thousand, nine hundred six".