101891 has 2 divisors, whose sum is σ = 101892. Its totient is φ = 101890.

The previous prime is 101879. The next prime is 101917. The reversal of 101891 is 198101.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-101891 is a prime.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (104891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50945 + 50946.

It is an arithmetic number, because the mean of its divisors is an integer number (50946).

2¹⁰¹⁸⁹¹ is an apocalyptic number.

101891 is a deficient number, since it is larger than the sum of its proper divisors (1).

101891 is an equidigital number, since it uses as much as digits as its factorization.

101891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 101891 is about 319.2036967204. The cubic root of 101891 is about 46.7066380891.

Adding to 101891 its reverse (198101), we get a palindrome (299992).

The spelling of 101891 in words is "one hundred one thousand, eight hundred ninety-one".