1291665567 has 4 divisors (see below), whose sum is σ = 1722220760. Its totient is φ = 861110376.

The previous prime is 1291665547. The next prime is 1291665601. The reversal of 1291665567 is 7655661921.

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

It is not a de Polignac number, because 1291665567 - 2⁶ = 1291665503 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 (1291665527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215277592 + ... + 215277597.

It is an arithmetic number, because the mean of its divisors is an integer number (430555190).

Almost surely, 2^1291665567 is an apocalyptic number.

1291665567 is a deficient number, since it is larger than the sum of its proper divisors (430555193).

1291665567 is an equidigital number, since it uses as much as digits as its factorization.

1291665567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430555192.

The product of its digits is 680400, while the sum is 48.

The square root of 1291665567 is about 35939.7491226636. The cubic root of 1291665567 is about 1089.0555371235.

The spelling of 1291665567 in words is "one billion, two hundred ninety-one million, six hundred sixty-five thousand, five hundred sixty-seven".