1985143849 has 4 divisors (see below), whose sum is σ = 2137847236. Its totient is φ = 1832440464.

The previous prime is 1985143819. The next prime is 1985143859. The reversal of 1985143849 is 9483415891.

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 214417449 + 1770726400 = 14643^2 + 42080^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985143849 - 2⁵ = 1985143817 is a prime.

It is a super-2 number, since 2×1985143849² = 7881592202445069602, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1985143796 and 1985143805.

It is not an unprimeable number, because it can be changed into a prime (1985143819) 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, 76351674 + ... + 76351699.

It is an arithmetic number, because the mean of its divisors is an integer number (534461809).

Almost surely, 2^1985143849 is an apocalyptic number.

It is an amenable number.

1985143849 is a deficient number, since it is larger than the sum of its proper divisors (152703387).

1985143849 is a wasteful number, since it uses less digits than its factorization.

1985143849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152703386.

The product of its digits is 1244160, while the sum is 52.

The square root of 1985143849 is about 44554.9531365481. The cubic root of 1985143849 is about 1256.7936974343.

The spelling of 1985143849 in words is "one billion, nine hundred eighty-five million, one hundred forty-three thousand, eight hundred forty-nine".