2131897891 has 2 divisors, whose sum is σ = 2131897892. Its totient is φ = 2131897890.

The previous prime is 2131897883. The next prime is 2131897897. The reversal of 2131897891 is 1987981312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2131897891 - 2³ = 2131897883 is a prime.

It is not a weakly prime, because it can be changed into another prime (2131897897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1065948945 + 1065948946.

It is an arithmetic number, because the mean of its divisors is an integer number (1065948946).

Almost surely, 2^2131897891 is an apocalyptic number.

2131897891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131897891 is an equidigital number, since it uses as much as digits as its factorization.

2131897891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 49.

The square root of 2131897891 is about 46172.4798012842. The cubic root of 2131897891 is about 1287.0303846215.

The spelling of 2131897891 in words is "two billion, one hundred thirty-one million, eight hundred ninety-seven thousand, eight hundred ninety-one".