987899989 has 2 divisors, whose sum is σ = 987899990. Its totient is φ = 987899988.

The previous prime is 987899929. The next prime is 987899999. The reversal of 987899989 is 989998789.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 679019364 + 308880625 = 26058^2 + 17575^2 .

It is a cyclic number.

It is not a de Polignac number, because 987899989 - 2⁹ = 987899477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (987899929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 493949994 + 493949995.

It is an arithmetic number, because the mean of its divisors is an integer number (493949995).

Almost surely, 2^987899989 is an apocalyptic number.

It is an amenable number.

987899989 is a deficient number, since it is larger than the sum of its proper divisors (1).

987899989 is an equidigital number, since it uses as much as digits as its factorization.

987899989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 211631616, while the sum is 76.

The square root of 987899989 is about 31430.8763638560. The cubic root of 987899989 is about 995.9502849467.

The spelling of 987899989 in words is "nine hundred eighty-seven million, eight hundred ninety-nine thousand, nine hundred eighty-nine".