1291759621 has 2 divisors, whose sum is σ = 1291759622. Its totient is φ = 1291759620.

The previous prime is 1291759597. The next prime is 1291759639. The reversal of 1291759621 is 1269571921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1283430625 + 8328996 = 35825^2 + 2886^2 .

It is an emirp because it is prime and its reverse (1269571921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291759621 - 2⁵ = 1291759589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291759661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645879810 + 645879811.

It is an arithmetic number, because the mean of its divisors is an integer number (645879811).

Almost surely, 2^1291759621 is an apocalyptic number.

It is an amenable number.

1291759621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291759621 is an equidigital number, since it uses as much as digits as its factorization.

1291759621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 43.

The square root of 1291759621 is about 35941.0575943447. The cubic root of 1291759621 is about 1089.0819700605.

The spelling of 1291759621 in words is "one billion, two hundred ninety-one million, seven hundred fifty-nine thousand, six hundred twenty-one".