197401891 has 2 divisors, whose sum is σ = 197401892. Its totient is φ = 197401890.

The previous prime is 197401889. The next prime is 197401903. The reversal of 197401891 is 198104791.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 197401891 - 2¹ = 197401889 is a prime.

Together with 197401889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (197401861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98700945 + 98700946.

It is an arithmetic number, because the mean of its divisors is an integer number (98700946).

Almost surely, 2^197401891 is an apocalyptic number.

197401891 is a deficient number, since it is larger than the sum of its proper divisors (1).

197401891 is an equidigital number, since it uses as much as digits as its factorization.

197401891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 40.

The square root of 197401891 is about 14049.9783273854. The cubic root of 197401891 is about 582.2601968702.

The spelling of 197401891 in words is "one hundred ninety-seven million, four hundred one thousand, eight hundred ninety-one".