198891397 has 4 divisors (see below), whose sum is σ = 199901196. Its totient is φ = 197881600.

The previous prime is 198891379. The next prime is 198891401. The reversal of 198891397 is 793198891.

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 120143521 + 78747876 = 10961^2 + 8874^2 .

It is a cyclic number.

It is not a de Polignac number, because 198891397 - 2²³ = 190502789 is a prime.

It is a super-2 number, since 2×198891397² = 79115575601223218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198891197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504604 + ... + 504997.

It is an arithmetic number, because the mean of its divisors is an integer number (49975299).

Almost surely, 2^198891397 is an apocalyptic number.

It is an amenable number.

198891397 is a deficient number, since it is larger than the sum of its proper divisors (1009799).

198891397 is a wasteful number, since it uses less digits than its factorization.

198891397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009798.

The product of its digits is 979776, while the sum is 55.

The square root of 198891397 is about 14102.8861230601. The cubic root of 198891397 is about 583.7210200709.

The spelling of 198891397 in words is "one hundred ninety-eight million, eight hundred ninety-one thousand, three hundred ninety-seven".