78199985 has 4 divisors (see below), whose sum is σ = 93839988. Its totient is φ = 62559984.

The previous prime is 78199951. The next prime is 78199999. The reversal of 78199985 is 58999187.

It is a happy number.

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 51739249 + 26460736 = 7193^2 + 5144^2 .

It is a cyclic number.

It is not a de Polignac number, because 78199985 - 2¹⁰ = 78198961 is a prime.

It is a super-2 number, since 2×78199985² = 12230475308000450, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78199985.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 7819994 + ... + 7820003.

It is an arithmetic number, because the mean of its divisors is an integer number (23459997).

Almost surely, 2^78199985 is an apocalyptic number.

It is an amenable number.

78199985 is a deficient number, since it is larger than the sum of its proper divisors (15640003).

78199985 is a wasteful number, since it uses less digits than its factorization.

78199985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15640002.

The product of its digits is 1632960, while the sum is 56.

The square root of 78199985 is about 8843.0755396525. The cubic root of 78199985 is about 427.6307136507.

The spelling of 78199985 in words is "seventy-eight million, one hundred ninety-nine thousand, nine hundred eighty-five".