999799987 has 2 divisors, whose sum is σ = 999799988. Its totient is φ = 999799986.

The previous prime is 999799981. The next prime is 999800059. The reversal of 999799987 is 789997999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999799987 - 2³ = 999799979 is a prime.

It is not a weakly prime, because it can be changed into another prime (999799981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499899993 + 499899994.

It is an arithmetic number, because the mean of its divisors is an integer number (499899994).

Almost surely, 2^999799987 is an apocalyptic number.

999799987 is a deficient number, since it is larger than the sum of its proper divisors (1).

999799987 is an equidigital number, since it uses as much as digits as its factorization.

999799987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 208324872, while the sum is 76.

The square root of 999799987 is about 31619.6139603253. The cubic root of 999799987 is about 999.9333245545.

The spelling of 999799987 in words is "nine hundred ninety-nine million, seven hundred ninety-nine thousand, nine hundred eighty-seven".