1998997688 has 16 divisors (see below), whose sum is σ = 3775481280. Its totient is φ = 992202688.

The previous prime is 1998997667. The next prime is 1998997711. The reversal of 1998997688 is 8867998991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 910856 + ... + 913047.

It is an arithmetic number, because the mean of its divisors is an integer number (235967580).

Almost surely, 2^1998997688 is an apocalyptic number.

It is an amenable number.

1998997688 is a deficient number, since it is larger than the sum of its proper divisors (1776483592).

1998997688 is a wasteful number, since it uses less digits than its factorization.

1998997688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1824046 (or 1824042 counting only the distinct ones).

The product of its digits is 141087744, while the sum is 74.

The square root of 1998997688 is about 44710.1519567984. The cubic root of 1998997688 is about 1259.7105423940.

The spelling of 1998997688 in words is "one billion, nine hundred ninety-eight million, nine hundred ninety-seven thousand, six hundred eighty-eight".