1985857313 has 4 divisors (see below), whose sum is σ = 2166389808. Its totient is φ = 1805324820.

The previous prime is 1985857297. The next prime is 1985857319. The reversal of 1985857313 is 3137585891.

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, and also an emirpimes, since its reverse is a distinct semiprime: 3137585891 = 11 ⋅285235081.

It is a cyclic number.

It is not a de Polignac number, because 1985857313 - 2⁴ = 1985857297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1985857319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90266231 + ... + 90266252.

It is an arithmetic number, because the mean of its divisors is an integer number (541597452).

Almost surely, 2^1985857313 is an apocalyptic number.

It is an amenable number.

1985857313 is a deficient number, since it is larger than the sum of its proper divisors (180532495).

1985857313 is a wasteful number, since it uses less digits than its factorization.

1985857313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180532494.

The product of its digits is 907200, while the sum is 50.

The square root of 1985857313 is about 44562.9589794035. The cubic root of 1985857313 is about 1256.9442439817.

The spelling of 1985857313 in words is "one billion, nine hundred eighty-five million, eight hundred fifty-seven thousand, three hundred thirteen".