128640211 has 4 divisors (see below), whose sum is σ = 147017392. Its totient is φ = 110263032.

The previous prime is 128640199. The next prime is 128640221. The reversal of 128640211 is 112046821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 128640211 - 2⁹ = 128639699 is a prime.

It is a super-2 number, since 2×128640211² = 33096607772249042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128640221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9188580 + ... + 9188593.

It is an arithmetic number, because the mean of its divisors is an integer number (36754348).

Almost surely, 2^128640211 is an apocalyptic number.

128640211 is a deficient number, since it is larger than the sum of its proper divisors (18377181).

128640211 is an equidigital number, since it uses as much as digits as its factorization.

128640211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18377180.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 128640211 is about 11341.9668047478. The cubic root of 128640211 is about 504.8072472888.

The spelling of 128640211 in words is "one hundred twenty-eight million, six hundred forty thousand, two hundred eleven".