78587217 has 6 divisors (see below), whose sum is σ = 113514882. Its totient is φ = 52391472.

The previous prime is 78587203. The next prime is 78587231. The reversal of 78587217 is 71278587.

It is an interprime number because it is at equal distance from previous prime (78587203) and next prime (78587231).

It can be written as a sum of positive squares in only one way, i.e., 78216336 + 370881 = 8844^2 + 609^2 .

It is not a de Polignac number, because 78587217 - 2²⁶ = 11478353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78587237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4365948 + ... + 4365965.

It is an arithmetic number, because the mean of its divisors is an integer number (18919147).

Almost surely, 2^78587217 is an apocalyptic number.

It is an amenable number.

78587217 is a deficient number, since it is larger than the sum of its proper divisors (34927665).

78587217 is a wasteful number, since it uses less digits than its factorization.

78587217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8731919 (or 8731916 counting only the distinct ones).

The product of its digits is 219520, while the sum is 45.

The square root of 78587217 is about 8864.9431470258. The cubic root of 78587217 is about 428.3354014176.

The spelling of 78587217 in words is "seventy-eight million, five hundred eighty-seven thousand, two hundred seventeen".