78520017 has 8 divisors (see below), whose sum is σ = 104980096. Its totient is φ = 52203312.

The previous prime is 78520007. The next prime is 78520019. The reversal of 78520017 is 71002587.

It is a happy number.

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

It is not a de Polignac number, because 78520017 - 2¹¹ = 78517969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78520019) 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, 34558 + ... + 36759.

It is an arithmetic number, because the mean of its divisors is an integer number (13122512).

Almost surely, 2^78520017 is an apocalyptic number.

It is an amenable number.

78520017 is a deficient number, since it is larger than the sum of its proper divisors (26460079).

78520017 is a wasteful number, since it uses less digits than its factorization.

78520017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71687.

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 78520017 is about 8861.1521259935. The cubic root of 78520017 is about 428.2132766055.

It can be divided in two parts, 785 and 20017, that added together give a palindrome (20802).

The spelling of 78520017 in words is "seventy-eight million, five hundred twenty thousand, seventeen".