198747891 has 8 divisors (see below), whose sum is σ = 294441360. Its totient is φ = 132498576.

The previous prime is 198747889. The next prime is 198747907.

198747891 is a `hidden beast` number, since 1 + 9 + 87 + 478 + 91 = 666.

198747891 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 198747891 - 2¹ = 198747889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (198747811) 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 7 ways as a sum of consecutive naturals, for example, 3680490 + ... + 3680543.

It is an arithmetic number, because the mean of its divisors is an integer number (36805170).

Almost surely, 2^198747891 is an apocalyptic number.

198747891 is a deficient number, since it is larger than the sum of its proper divisors (95693469).

198747891 is an equidigital number, since it uses as much as digits as its factorization.

198747891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7361042 (or 7361036 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 198747891 is about 14097.7973811514. The cubic root of 198747891 is about 583.5805956568.

The spelling of 198747891 in words is "one hundred ninety-eight million, seven hundred forty-seven thousand, eight hundred ninety-one".