1866217985 has 8 divisors (see below), whose sum is σ = 2250076416. Its totient is φ = 1485897840.

The previous prime is 1866217979. The next prime is 1866218041. The reversal of 1866217985 is 5897126681.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1866217985 - 2¹⁸ = 1865955841 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 883409 + ... + 885518.

It is an arithmetic number, because the mean of its divisors is an integer number (281259552).

Almost surely, 2^1866217985 is an apocalyptic number.

It is an amenable number.

1866217985 is a deficient number, since it is larger than the sum of its proper divisors (383858431).

1866217985 is a wasteful number, since it uses less digits than its factorization.

1866217985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769143.

The product of its digits is 1451520, while the sum is 53.

The square root of 1866217985 is about 43199.7451960078. The cubic root of 1866217985 is about 1231.1778403947.

The spelling of 1866217985 in words is "one billion, eight hundred sixty-six million, two hundred seventeen thousand, nine hundred eighty-five".