128736665 has 8 divisors (see below), whose sum is σ = 163571400. Its totient is φ = 96931072.

The previous prime is 128736661. The next prime is 128736667. The reversal of 128736665 is 566637821.

It can be written as a sum of positive squares in 4 ways, for example, as 61889689 + 66846976 = 7867^2 + 8176^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128736665 - 2² = 128736661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128736661) 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, 757190 + ... + 757359.

It is an arithmetic number, because the mean of its divisors is an integer number (20446425).

Almost surely, 2^128736665 is an apocalyptic number.

It is an amenable number.

128736665 is a deficient number, since it is larger than the sum of its proper divisors (34834735).

128736665 is a wasteful number, since it uses less digits than its factorization.

128736665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1514571.

The product of its digits is 362880, while the sum is 44.

The square root of 128736665 is about 11346.2180923866. The cubic root of 128736665 is about 504.9333833638.

The spelling of 128736665 in words is "one hundred twenty-eight million, seven hundred thirty-six thousand, six hundred sixty-five".