1861985 has 4 divisors (see below), whose sum is σ = 2234388. Its totient is φ = 1489584.

The previous prime is 1861973. The next prime is 1861991. The reversal of 1861985 is 5891681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5891681 = 59 ⋅99859.

It can be written as a sum of positive squares in 2 ways, for example, as 192721 + 1669264 = 439^2 + 1292^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861985 - 2⁶ = 1861921 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 186194 + ... + 186203.

It is an arithmetic number, because the mean of its divisors is an integer number (558597).

2^1861985 is an apocalyptic number.

It is an amenable number.

1861985 is a deficient number, since it is larger than the sum of its proper divisors (372403).

1861985 is an equidigital number, since it uses as much as digits as its factorization.

1861985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372402.

The product of its digits is 17280, while the sum is 38.

The square root of 1861985 is about 1364.5457119496. The cubic root of 1861985 is about 123.0246276726.

The spelling of 1861985 in words is "one million, eight hundred sixty-one thousand, nine hundred eighty-five".