998778899 has 2 divisors, whose sum is σ = 998778900. Its totient is φ = 998778898.

The previous prime is 998778877. The next prime is 998778953. The reversal of 998778899 is 998877899.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-998778899 is a prime.

It is not a weakly prime, because it can be changed into another prime (998778829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499389449 + 499389450.

It is an arithmetic number, because the mean of its divisors is an integer number (499389450).

Almost surely, 2^998778899 is an apocalyptic number.

998778899 is a deficient number, since it is larger than the sum of its proper divisors (1).

998778899 is an equidigital number, since it uses as much as digits as its factorization.

998778899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164602368, while the sum is 74.

The square root of 998778899 is about 31603.4634019754. The cubic root of 998778899 is about 999.5928005444.

The spelling of 998778899 in words is "nine hundred ninety-eight million, seven hundred seventy-eight thousand, eight hundred ninety-nine".