2131878961 has 2 divisors, whose sum is σ = 2131878962. Its totient is φ = 2131878960.

The previous prime is 2131878953. The next prime is 2131878977. The reversal of 2131878961 is 1698781312.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1663416225 + 468462736 = 40785^2 + 21644^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131878961 - 2³ = 2131878953 is a prime.

It is not a weakly prime, because it can be changed into another prime (2131878361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1065939480 + 1065939481.

It is an arithmetic number, because the mean of its divisors is an integer number (1065939481).

Almost surely, 2^2131878961 is an apocalyptic number.

It is an amenable number.

2131878961 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131878961 is an equidigital number, since it uses as much as digits as its factorization.

2131878961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 46.

The square root of 2131878961 is about 46172.2748085905. The cubic root of 2131878961 is about 1287.0265752525.

The spelling of 2131878961 in words is "two billion, one hundred thirty-one million, eight hundred seventy-eight thousand, nine hundred sixty-one".