9990998987 has 2 divisors, whose sum is σ = 9990998988. Its totient is φ = 9990998986.

The previous prime is 9990998971. The next prime is 9990999019. The reversal of 9990998987 is 7898990999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9990998987 - 2⁴ = 9990998971 is a prime.

It is not a weakly prime, because it can be changed into another prime (9990998917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995499493 + 4995499494.

It is an arithmetic number, because the mean of its divisors is an integer number (4995499494).

Almost surely, 2^9990998987 is an apocalyptic number.

9990998987 is a deficient number, since it is larger than the sum of its proper divisors (1).

9990998987 is an equidigital number, since it uses as much as digits as its factorization.

9990998987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 238085568, while the sum is 77.

The square root of 9990998987 is about 99954.9848031603. The cubic root of 9990998987 is about 2153.7880928370.

The spelling of 9990998987 in words is "nine billion, nine hundred ninety million, nine hundred ninety-eight thousand, nine hundred eighty-seven".