78865987 has 4 divisors (see below), whose sum is σ = 79021440. Its totient is φ = 78710536.

The previous prime is 78865939. The next prime is 78865991. The reversal of 78865987 is 78956887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78956887 = 67 ⋅1178461.

It is a cyclic number.

It is not a de Polignac number, because 78865987 - 2¹⁵ = 78833219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78865187) 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 3 ways as a sum of consecutive naturals, for example, 76963 + ... + 77980.

It is an arithmetic number, because the mean of its divisors is an integer number (19755360).

Almost surely, 2^78865987 is an apocalyptic number.

78865987 is a deficient number, since it is larger than the sum of its proper divisors (155453).

78865987 is a wasteful number, since it uses less digits than its factorization.

78865987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155452.

The product of its digits is 6773760, while the sum is 58.

The square root of 78865987 is about 8880.6523972060. The cubic root of 78865987 is about 428.8412773617.

The spelling of 78865987 in words is "seventy-eight million, eight hundred sixty-five thousand, nine hundred eighty-seven".