1291567391 has 4 divisors (see below), whose sum is σ = 1293082392. Its totient is φ = 1290052392.

The previous prime is 1291567373. The next prime is 1291567411. The reversal of 1291567391 is 1937651921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1291567391 - 2¹⁸ = 1291305247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291567891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 756221 + ... + 757926.

It is an arithmetic number, because the mean of its divisors is an integer number (323270598).

Almost surely, 2^1291567391 is an apocalyptic number.

1291567391 is a deficient number, since it is larger than the sum of its proper divisors (1515001).

1291567391 is an equidigital number, since it uses as much as digits as its factorization.

1291567391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1515000.

The product of its digits is 102060, while the sum is 44.

The square root of 1291567391 is about 35938.3832552328. The cubic root of 1291567391 is about 1089.0279443709.

The spelling of 1291567391 in words is "one billion, two hundred ninety-one million, five hundred sixty-seven thousand, three hundred ninety-one".