128709805 has 16 divisors (see below), whose sum is σ = 186900480. Its totient is φ = 83066112.

The previous prime is 128709803. The next prime is 128709809. The reversal of 128709805 is 508907821.

It is a cyclic number.

It is not a de Polignac number, because 128709805 - 2¹ = 128709803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128709803) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107565 + ... + 108754.

It is an arithmetic number, because the mean of its divisors is an integer number (11681280).

Almost surely, 2^128709805 is an apocalyptic number.

It is an amenable number.

128709805 is a deficient number, since it is larger than the sum of its proper divisors (58190675).

128709805 is a wasteful number, since it uses less digits than its factorization.

128709805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216348.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 128709805 is about 11345.0343763252. The cubic root of 128709805 is about 504.8982639878.

The spelling of 128709805 in words is "one hundred twenty-eight million, seven hundred nine thousand, eight hundred five".