971995891 has 2 divisors, whose sum is σ = 971995892. Its totient is φ = 971995890.

The previous prime is 971995889. The next prime is 971995933. The reversal of 971995891 is 198599179.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 971995891 - 2¹ = 971995889 is a prime.

Together with 971995889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (971995831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 485997945 + 485997946.

It is an arithmetic number, because the mean of its divisors is an integer number (485997946).

Almost surely, 2^971995891 is an apocalyptic number.

971995891 is a deficient number, since it is larger than the sum of its proper divisors (1).

971995891 is an equidigital number, since it uses as much as digits as its factorization.

971995891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1837080, while the sum is 58.

The square root of 971995891 is about 31176.8486380519. The cubic root of 971995891 is about 990.5767788208.

The spelling of 971995891 in words is "nine hundred seventy-one million, nine hundred ninety-five thousand, eight hundred ninety-one".