78817265 has 4 divisors (see below), whose sum is σ = 94580724. Its totient is φ = 63053808.

The previous prime is 78817247. The next prime is 78817267. The reversal of 78817265 is 56271887.

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

It can be written as a sum of positive squares in 2 ways, for example, as 41460721 + 37356544 = 6439^2 + 6112^2 .

It is a cyclic number.

It is not a de Polignac number, because 78817265 - 2⁸ = 78817009 is a prime.

It is a super-2 number, since 2×78817265² = 12424322524160450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78817267) 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, 7881722 + ... + 7881731.

It is an arithmetic number, because the mean of its divisors is an integer number (23645181).

Almost surely, 2^78817265 is an apocalyptic number.

It is an amenable number.

78817265 is a deficient number, since it is larger than the sum of its proper divisors (15763459).

78817265 is a wasteful number, since it uses less digits than its factorization.

78817265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15763458.

The product of its digits is 188160, while the sum is 44.

The square root of 78817265 is about 8877.9088190857. The cubic root of 78817265 is about 428.7529490061.

The spelling of 78817265 in words is "seventy-eight million, eight hundred seventeen thousand, two hundred sixty-five".