1291731941 has 2 divisors, whose sum is σ = 1291731942. Its totient is φ = 1291731940.

The previous prime is 1291731877. The next prime is 1291731943. The reversal of 1291731941 is 1491371921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 957902500 + 333829441 = 30950^2 + 18271^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291731941 - 2⁶ = 1291731877 is a prime.

Together with 1291731943, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1291731895 and 1291731904.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291731943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645865970 + 645865971.

It is an arithmetic number, because the mean of its divisors is an integer number (645865971).

Almost surely, 2^1291731941 is an apocalyptic number.

It is an amenable number.

1291731941 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291731941 is an equidigital number, since it uses as much as digits as its factorization.

1291731941 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13608, while the sum is 38.

The square root of 1291731941 is about 35940.6725173584. The cubic root of 1291731941 is about 1089.0741910063.

The spelling of 1291731941 in words is "one billion, two hundred ninety-one million, seven hundred thirty-one thousand, nine hundred forty-one".