197090891 has 2 divisors, whose sum is σ = 197090892. Its totient is φ = 197090890.

The previous prime is 197090867. The next prime is 197090893. The reversal of 197090891 is 198090791.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 197090891 - 2⁶ = 197090827 is a prime.

It is a Sophie Germain prime.

Together with 197090893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (197090893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98545445 + 98545446.

It is an arithmetic number, because the mean of its divisors is an integer number (98545446).

Almost surely, 2^197090891 is an apocalyptic number.

197090891 is a deficient number, since it is larger than the sum of its proper divisors (1).

197090891 is an equidigital number, since it uses as much as digits as its factorization.

197090891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 197090891 is about 14038.9063320474. The cubic root of 197090891 is about 581.9542590694.

The spelling of 197090891 in words is "one hundred ninety-seven million, ninety thousand, eight hundred ninety-one".