198871591 has 4 divisors (see below), whose sum is σ = 200730312. Its totient is φ = 197012872.

The previous prime is 198871583. The next prime is 198871643. The reversal of 198871591 is 195178891.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 198871591 - 2³ = 198871583 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 (198871571) 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, 929200 + ... + 929413.

It is an arithmetic number, because the mean of its divisors is an integer number (50182578).

Almost surely, 2^198871591 is an apocalyptic number.

198871591 is a deficient number, since it is larger than the sum of its proper divisors (1858721).

198871591 is a wasteful number, since it uses less digits than its factorization.

198871591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1858720.

The product of its digits is 181440, while the sum is 49.

The square root of 198871591 is about 14102.1839088845. The cubic root of 198871591 is about 583.7016433952.

The spelling of 198871591 in words is "one hundred ninety-eight million, eight hundred seventy-one thousand, five hundred ninety-one".