78999987 has 16 divisors (see below), whose sum is σ = 117583488. Its totient is φ = 46764480.

The previous prime is 78999979. The next prime is 79000007.

78999987 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 78999987 - 2³ = 78999979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78999937) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26418 + ... + 29255.

It is an arithmetic number, because the mean of its divisors is an integer number (7348968).

Almost surely, 2^78999987 is an apocalyptic number.

78999987 is a deficient number, since it is larger than the sum of its proper divisors (38583501).

78999987 is a wasteful number, since it uses less digits than its factorization.

78999987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55730.

The product of its digits is 20575296, while the sum is 66.

The square root of 78999987 is about 8888.1936860084. The cubic root of 78999987 is about 429.0840191664.

The spelling of 78999987 in words is "seventy-eight million, nine hundred ninety-nine thousand, nine hundred eighty-seven".