1291542557 has 2 divisors, whose sum is σ = 1291542558. Its totient is φ = 1291542556.

The previous prime is 1291542541. The next prime is 1291542559. The reversal of 1291542557 is 7552451921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 935503396 + 356039161 = 30586^2 + 18869^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291542557 - 2⁴ = 1291542541 is a prime.

Together with 1291542559, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291542559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645771278 + 645771279.

It is an arithmetic number, because the mean of its divisors is an integer number (645771279).

Almost surely, 2^1291542557 is an apocalyptic number.

It is an amenable number.

1291542557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291542557 is an equidigital number, since it uses as much as digits as its factorization.

1291542557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 126000, while the sum is 41.

The square root of 1291542557 is about 35938.0377455420. The cubic root of 1291542557 is about 1089.0209644555.

The spelling of 1291542557 in words is "one billion, two hundred ninety-one million, five hundred forty-two thousand, five hundred fifty-seven".