9999979987 has 2 divisors, whose sum is σ = 9999979988. Its totient is φ = 9999979986.

The previous prime is 9999979981. The next prime is 9999979993. The reversal of 9999979987 is 7899799999.

It is a balanced prime because it is at equal distance from previous prime (9999979981) and next prime (9999979993).

It is a cyclic number.

It is not a de Polignac number, because 9999979987 - 2²⁷ = 9865762259 is a prime.

It is not a weakly prime, because it can be changed into another prime (9999979981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999989993 + 4999989994.

It is an arithmetic number, because the mean of its divisors is an integer number (4999989994).

Almost surely, 2^9999979987 is an apocalyptic number.

9999979987 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999979987 is an equidigital number, since it uses as much as digits as its factorization.

9999979987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1874923848, while the sum is 85.

The square root of 9999979987 is about 99999.8999349499. The cubic root of 9999979987 is about 2154.4332528075.

The spelling of 9999979987 in words is "nine billion, nine hundred ninety-nine million, nine hundred seventy-nine thousand, nine hundred eighty-seven".