1291669849 has 2 divisors, whose sum is σ = 1291669850. Its totient is φ = 1291669848.

The previous prime is 1291669817. The next prime is 1291669861. The reversal of 1291669849 is 9489661921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 865536400 + 426133449 = 29420^2 + 20643^2 .

It is an emirp because it is prime and its reverse (9489661921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291669849 - 2⁵ = 1291669817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1291669849.

It is not a weakly prime, because it can be changed into another prime (1291669879) 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 as a sum of consecutive naturals, namely, 645834924 + 645834925.

It is an arithmetic number, because the mean of its divisors is an integer number (645834925).

Almost surely, 2^1291669849 is an apocalyptic number.

It is an amenable number.

1291669849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291669849 is an equidigital number, since it uses as much as digits as its factorization.

1291669849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1679616, while the sum is 55.

The square root of 1291669849 is about 35939.8086945381. The cubic root of 1291669849 is about 1089.0567405647.

The spelling of 1291669849 in words is "one billion, two hundred ninety-one million, six hundred sixty-nine thousand, eight hundred forty-nine".