1865221985 has 16 divisors (see below), whose sum is σ = 2507740992. Its totient is φ = 1319860800.

The previous prime is 1865221937. The next prime is 1865221991. The reversal of 1865221985 is 5891225681.

It is not a de Polignac number, because 1865221985 - 2²⁴ = 1848444769 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 456251 + ... + 460320.

It is an arithmetic number, because the mean of its divisors is an integer number (156733812).

Almost surely, 2^1865221985 is an apocalyptic number.

It is an amenable number.

1865221985 is a deficient number, since it is larger than the sum of its proper divisors (642519007).

1865221985 is a wasteful number, since it uses less digits than its factorization.

1865221985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916624.

The product of its digits is 345600, while the sum is 47.

The square root of 1865221985 is about 43188.2158117235. The cubic root of 1865221985 is about 1230.9587749990.

The spelling of 1865221985 in words is "one billion, eight hundred sixty-five million, two hundred twenty-one thousand, nine hundred eighty-five".