128972709 has 8 divisors (see below), whose sum is σ = 191070720. Its totient is φ = 85981788.

The previous prime is 128972689. The next prime is 128972717. The reversal of 128972709 is 907279821.

It is not a de Polignac number, because 128972709 - 2⁷ = 128972581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128972749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2388357 + ... + 2388410.

It is an arithmetic number, because the mean of its divisors is an integer number (23883840).

Almost surely, 2^128972709 is an apocalyptic number.

It is an amenable number.

128972709 is a deficient number, since it is larger than the sum of its proper divisors (62098011).

128972709 is an equidigital number, since it uses as much as digits as its factorization.

128972709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4776776 (or 4776770 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 128972709 is about 11356.6152087671. The cubic root of 128972709 is about 505.2418003565.

The spelling of 128972709 in words is "one hundred twenty-eight million, nine hundred seventy-two thousand, seven hundred nine".