128129665 has 32 divisors (see below), whose sum is σ = 167510016. Its totient is φ = 93804480.

The previous prime is 128129657. The next prime is 128129669. The reversal of 128129665 is 566921821.

It is not a de Polignac number, because 128129665 - 2³ = 128129657 is a prime.

It is a super-2 number, since 2×128129665² = 32834422106024450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128129669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 452614 + ... + 452896.

It is an arithmetic number, because the mean of its divisors is an integer number (5234688).

Almost surely, 2^128129665 is an apocalyptic number.

It is an amenable number.

128129665 is a deficient number, since it is larger than the sum of its proper divisors (39380351).

128129665 is a wasteful number, since it uses less digits than its factorization.

128129665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469.

The product of its digits is 51840, while the sum is 40.

The square root of 128129665 is about 11319.4374860238. The cubic root of 128129665 is about 504.1385371764.

The spelling of 128129665 in words is "one hundred twenty-eight million, one hundred twenty-nine thousand, six hundred sixty-five".