198787217 has 4 divisors (see below), whose sum is σ = 198887220. Its totient is φ = 198687216.

The previous prime is 198787181. The next prime is 198787243. The reversal of 198787217 is 712787891.

It is a happy number.

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 198274561 + 512656 = 14081^2 + 716^2 .

It is a cyclic number.

It is not a de Polignac number, because 198787217 - 2⁸ = 198786961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198787247) 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, 46958 + ... + 51015.

It is an arithmetic number, because the mean of its divisors is an integer number (49721805).

Almost surely, 2^198787217 is an apocalyptic number.

It is an amenable number.

198787217 is a deficient number, since it is larger than the sum of its proper divisors (100003).

198787217 is an equidigital number, since it uses as much as digits as its factorization.

198787217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100002.

The product of its digits is 395136, while the sum is 50.

The square root of 198787217 is about 14099.1920690513. The cubic root of 198787217 is about 583.6190839092.

The spelling of 198787217 in words is "one hundred ninety-eight million, seven hundred eighty-seven thousand, two hundred seventeen".