998778897 has 8 divisors (see below), whose sum is σ = 1479672480. Its totient is φ = 665852580.

The previous prime is 998778877. The next prime is 998778899. The reversal of 998778897 is 798877899.

It is not a de Polignac number, because 998778897 - 2²² = 994584593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (998778899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18495879 + ... + 18495932.

It is an arithmetic number, because the mean of its divisors is an integer number (184959060).

Almost surely, 2^998778897 is an apocalyptic number.

It is an amenable number.

998778897 is a deficient number, since it is larger than the sum of its proper divisors (480893583).

998778897 is a wasteful number, since it uses less digits than its factorization.

998778897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36991820 (or 36991814 counting only the distinct ones).

The product of its digits is 128024064, while the sum is 72.

The square root of 998778897 is about 31603.4633703333. The cubic root of 998778897 is about 999.5927998772.

The spelling of 998778897 in words is "nine hundred ninety-eight million, seven hundred seventy-eight thousand, eight hundred ninety-seven".