1998689688 has 32 divisors (see below), whose sum is σ = 5551916400. Its totient is φ = 666229824.

The previous prime is 1998689683. The next prime is 1998689699. The reversal of 1998689688 is 8869868991.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998689681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4626381 + ... + 4626812.

Almost surely, 2^1998689688 is an apocalyptic number.

1998689688 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1998689688 is an abundant number, since it is smaller than the sum of its proper divisors (3553226712).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1998689688 is a wasteful number, since it uses less digits than its factorization.

1998689688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9253208 (or 9253198 counting only the distinct ones).

The product of its digits is 107495424, while the sum is 72.

The square root of 1998689688 is about 44706.7074162256. The cubic root of 1998689688 is about 1259.6458415062.

The spelling of 1998689688 in words is "one billion, nine hundred ninety-eight million, six hundred eighty-nine thousand, six hundred eighty-eight".