1985258209 has 4 divisors (see below), whose sum is σ = 2165736240. Its totient is φ = 1804780180.

The previous prime is 1985258207. The next prime is 1985258243. The reversal of 1985258209 is 9028525891.

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 1985258209 - 2¹ = 1985258207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1985258203) 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, 90238999 + ... + 90239020.

It is an arithmetic number, because the mean of its divisors is an integer number (541434060).

Almost surely, 2^1985258209 is an apocalyptic number.

It is an amenable number.

1985258209 is a deficient number, since it is larger than the sum of its proper divisors (180478031).

1985258209 is a wasteful number, since it uses less digits than its factorization.

1985258209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180478030.

The product of its (nonzero) digits is 518400, while the sum is 49.

The square root of 1985258209 is about 44556.2364770635. The cubic root of 1985258209 is about 1256.8178307261.

The spelling of 1985258209 in words is "one billion, nine hundred eighty-five million, two hundred fifty-eight thousand, two hundred nine".