1998192785 has 4 divisors (see below), whose sum is σ = 2397831348. Its totient is φ = 1598554224.

The previous prime is 1998192773. The next prime is 1998192809. The reversal of 1998192785 is 5872918991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 508773136 + 1489419649 = 22556^2 + 38593^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998192785 - 2²² = 1993998481 is a prime.

It is a Duffinian 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, 199819274 + ... + 199819283.

It is an arithmetic number, because the mean of its divisors is an integer number (599457837).

Almost surely, 2^1998192785 is an apocalyptic number.

It is an amenable number.

1998192785 is a deficient number, since it is larger than the sum of its proper divisors (399638563).

1998192785 is an equidigital number, since it uses as much as digits as its factorization.

1998192785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399638562.

The product of its digits is 3265920, while the sum is 59.

The square root of 1998192785 is about 44701.1497055725. The cubic root of 1998192785 is about 1259.5414441637.

The spelling of 1998192785 in words is "one billion, nine hundred ninety-eight million, one hundred ninety-two thousand, seven hundred eighty-five".