78128065 has 8 divisors (see below), whose sum is σ = 93881448. Its totient is φ = 62417280.

The previous prime is 78128051. The next prime is 78128069. The reversal of 78128065 is 56082187.

It can be written as a sum of positive squares in 4 ways, for example, as 194481 + 77933584 = 441^2 + 8828^2 .

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

It is not a de Polignac number, because 78128065 - 2¹¹ = 78126017 is a prime.

It is a super-2 number, since 2×78128065² = 12207989081288450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78128069) 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, 6462 + ... + 14071.

It is an arithmetic number, because the mean of its divisors is an integer number (11735181).

Almost surely, 2^78128065 is an apocalyptic number.

It is an amenable number.

78128065 is a deficient number, since it is larger than the sum of its proper divisors (15753383).

78128065 is a wasteful number, since it uses less digits than its factorization.

78128065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21299.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 78128065 is about 8839.0081457141. The cubic root of 78128065 is about 427.4995770774.

The spelling of 78128065 in words is "seventy-eight million, one hundred twenty-eight thousand, sixty-five".