78815765 has 24 divisors (see below), whose sum is σ = 113824440. Its totient is φ = 52176768.

The previous prime is 78815761. The next prime is 78815771. The reversal of 78815765 is 56751887.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 19201924 + 59613841 = 4382^2 + 7721^2 .

It is not a de Polignac number, because 78815765 - 2² = 78815761 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78815761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1559 + ... + 12651.

It is an arithmetic number, because the mean of its divisors is an integer number (4742685).

Almost surely, 2^78815765 is an apocalyptic number.

It is an amenable number.

78815765 is a deficient number, since it is larger than the sum of its proper divisors (35008675).

78815765 is a wasteful number, since it uses less digits than its factorization.

78815765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11141 (or 11134 counting only the distinct ones).

The product of its digits is 470400, while the sum is 47.

The square root of 78815765 is about 8877.8243393300. The cubic root of 78815765 is about 428.7502290711.

The spelling of 78815765 in words is "seventy-eight million, eight hundred fifteen thousand, seven hundred sixty-five".