1985398189 has 4 divisors (see below), whose sum is σ = 1986147520. Its totient is φ = 1984648860.

The previous prime is 1985398183. The next prime is 1985398199. The reversal of 1985398189 is 9818935891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1985398189 - 2⁷ = 1985398061 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 (1985398183) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 370677 + ... + 375994.

It is an arithmetic number, because the mean of its divisors is an integer number (496536880).

Almost surely, 2^1985398189 is an apocalyptic number.

It is an amenable number.

1985398189 is a deficient number, since it is larger than the sum of its proper divisors (749331).

1985398189 is an equidigital number, since it uses as much as digits as its factorization.

1985398189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 749330.

The product of its digits is 5598720, while the sum is 61.

The square root of 1985398189 is about 44557.8072732490. The cubic root of 1985398189 is about 1256.8473693229.

The spelling of 1985398189 in words is "one billion, nine hundred eighty-five million, three hundred ninety-eight thousand, one hundred eighty-nine".