197981091 has 56 divisors (see below), whose sum is σ = 370185984. Its totient is φ = 102818160.

The previous prime is 197981081. The next prime is 197981093. The reversal of 197981091 is 190189791.

It is not a de Polignac number, because 197981091 - 2⁹ = 197980579 is a prime.

It is not an unprimeable number, because it can be changed into a prime (197981093) 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 55 ways as a sum of consecutive naturals, for example, 54370 + ... + 57896.

It is an arithmetic number, because the mean of its divisors is an integer number (6610464).

Almost surely, 2^197981091 is an apocalyptic number.

197981091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

197981091 is a deficient number, since it is larger than the sum of its proper divisors (172204893).

197981091 is an equidigital number, since it uses as much as digits as its factorization.

197981091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3563 (or 3548 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 45.

The square root of 197981091 is about 14070.5753613703. The cubic root of 197981091 is about 582.8291137504.

The spelling of 197981091 in words is "one hundred ninety-seven million, nine hundred eighty-one thousand, ninety-one".