1998197 has 4 divisors (see below), whose sum is σ = 2115756. Its totient is φ = 1880640.

The previous prime is 1998181. The next prime is 1998209. The reversal of 1998197 is 7918991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 763876 + 1234321 = 874^2 + 1111^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998197 - 2⁴ = 1998181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998107) 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, 58754 + ... + 58787.

It is an arithmetic number, because the mean of its divisors is an integer number (528939).

2^1998197 is an apocalyptic number.

1998197 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1998197 is a deficient number, since it is larger than the sum of its proper divisors (117559).

1998197 is a wasteful number, since it uses less digits than its factorization.

1998197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117558.

The product of its digits is 40824, while the sum is 44.

The square root of 1998197 is about 1413.5759618782. The cubic root of 1998197 is about 125.9542329791.

The spelling of 1998197 in words is "one million, nine hundred ninety-eight thousand, one hundred ninety-seven".