65128231 has 4 divisors (see below), whose sum is σ = 74432272. Its totient is φ = 55824192.

The previous prime is 65128223. The next prime is 65128253. The reversal of 65128231 is 13282156.

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 65128231 - 2³ = 65128223 is a prime.

It is a super-2 number, since 2×65128231² = 8483372946378722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65128231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65128201) 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, 4652010 + ... + 4652023.

It is an arithmetic number, because the mean of its divisors is an integer number (18608068).

Almost surely, 2^65128231 is an apocalyptic number.

65128231 is a deficient number, since it is larger than the sum of its proper divisors (9304041).

65128231 is an equidigital number, since it uses as much as digits as its factorization.

65128231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9304040.

The product of its digits is 2880, while the sum is 28.

The square root of 65128231 is about 8070.2063790215. The cubic root of 65128231 is about 402.3368030445.

It can be divided in two parts, 651 and 28231, that added together give a palindrome (28882).

The spelling of 65128231 in words is "sixty-five million, one hundred twenty-eight thousand, two hundred thirty-one".