1998865 has 8 divisors (see below), whose sum is σ = 2616768. Its totient is φ = 1453680.

The previous prime is 1998839. The next prime is 1998881. The reversal of 1998865 is 5688991.

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

It is not a de Polignac number, because 1998865 - 2¹¹ = 1996817 is a prime.

It is a super-2 number, since 2×1998865² = 7990922576450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18117 + ... + 18226.

It is an arithmetic number, because the mean of its divisors is an integer number (327096).

2^1998865 is an apocalyptic number.

It is an amenable number.

1998865 is a deficient number, since it is larger than the sum of its proper divisors (617903).

1998865 is a wasteful number, since it uses less digits than its factorization.

1998865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36359.

The product of its digits is 155520, while the sum is 46.

The square root of 1998865 is about 1413.8122223266. The cubic root of 1998865 is about 125.9682669730.

The spelling of 1998865 in words is "one million, nine hundred ninety-eight thousand, eight hundred sixty-five".