128265811 has 4 divisors (see below), whose sum is σ = 132688800. Its totient is φ = 123842824.

The previous prime is 128265763. The next prime is 128265829. The reversal of 128265811 is 118562821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 118562821 = 13 ⋅9120217.

It is a cyclic number.

It is not a de Polignac number, because 128265811 - 2⁹ = 128265299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128265881) 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, 2211451 + ... + 2211508.

It is an arithmetic number, because the mean of its divisors is an integer number (33172200).

Almost surely, 2^128265811 is an apocalyptic number.

128265811 is a deficient number, since it is larger than the sum of its proper divisors (4422989).

128265811 is an equidigital number, since it uses as much as digits as its factorization.

128265811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4422988.

The product of its digits is 7680, while the sum is 34.

The square root of 128265811 is about 11325.4497040956. The cubic root of 128265811 is about 504.3170338303.

The spelling of 128265811 in words is "one hundred twenty-eight million, two hundred sixty-five thousand, eight hundred eleven".