78724117 has 6 divisors (see below), whose sum is σ = 79084514. Its totient is φ = 78365280.

The previous prime is 78724111. The next prime is 78724157. The reversal of 78724117 is 71142787.

It can be written as a sum of positive squares in 3 ways, for example, as 38452401 + 40271716 = 6201^2 + 6346^2 .

It is not a de Polignac number, because 78724117 - 2³ = 78724109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78724111) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 78463 + ... + 79459.

Almost surely, 2^78724117 is an apocalyptic number.

It is an amenable number.

78724117 is a deficient number, since it is larger than the sum of its proper divisors (360397).

78724117 is an frugal number, since it uses more digits than its factorization.

78724117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1559 (or 1278 counting only the distinct ones).

The product of its digits is 21952, while the sum is 37.

The square root of 78724117 is about 8872.6612129620. The cubic root of 78724117 is about 428.5839791616.

The spelling of 78724117 in words is "seventy-eight million, seven hundred twenty-four thousand, one hundred seventeen".