1291531379 has 2 divisors, whose sum is σ = 1291531380. Its totient is φ = 1291531378.

The previous prime is 1291531343. The next prime is 1291531399. The reversal of 1291531379 is 9731351921.

It is a strong prime.

It is an emirp because it is prime and its reverse (9731351921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291531379 - 2¹² = 1291527283 is a prime.

It is not a weakly prime, because it can be changed into another prime (1291531309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645765689 + 645765690.

It is an arithmetic number, because the mean of its divisors is an integer number (645765690).

Almost surely, 2^1291531379 is an apocalyptic number.

1291531379 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291531379 is an equidigital number, since it uses as much as digits as its factorization.

1291531379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51030, while the sum is 41.

The square root of 1291531379 is about 35937.8822275326. The cubic root of 1291531379 is about 1089.0178227055.

The spelling of 1291531379 in words is "one billion, two hundred ninety-one million, five hundred thirty-one thousand, three hundred seventy-nine".