1998837391 has 8 divisors (see below), whose sum is σ = 2010160800. Its totient is φ = 1987527168.

The previous prime is 1998837367. The next prime is 1998837403. The reversal of 1998837391 is 1937388991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1998837391 - 2⁵ = 1998837359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998837301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 550815 + ... + 554431.

It is an arithmetic number, because the mean of its divisors is an integer number (251270100).

Almost surely, 2^1998837391 is an apocalyptic number.

1998837391 is a deficient number, since it is larger than the sum of its proper divisors (11323409).

1998837391 is a wasteful number, since it uses less digits than its factorization.

1998837391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6593.

The product of its digits is 2939328, while the sum is 58.

The square root of 1998837391 is about 44708.3592966684. The cubic root of 1998837391 is about 1259.6768699825.

The spelling of 1998837391 in words is "one billion, nine hundred ninety-eight million, eight hundred thirty-seven thousand, three hundred ninety-one".