79987 has 2 divisors, whose sum is σ = 79988. Its totient is φ = 79986.

The previous prime is 79979. The next prime is 79997. The reversal of 79987 is 78997.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 79987 - 2³ = 79979 is a prime.

It is not a weakly prime, because it can be changed into another prime (79907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39993 + 39994.

It is an arithmetic number, because the mean of its divisors is an integer number (39994).

2⁷⁹⁹⁸⁷ is an apocalyptic number.

79987 is a deficient number, since it is larger than the sum of its proper divisors (1).

79987 is an equidigital number, since it uses as much as digits as its factorization.

79987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31752, while the sum is 40.

The square root of 79987 is about 282.8197305706. The cubic root of 79987 is about 43.0863597033.

Subtracting from 79987 its reverse (78997), we obtain a triangular number (990 = T₄₄).

The spelling of 79987 in words is "seventy-nine thousand, nine hundred eighty-seven".