1291249723 has 2 divisors, whose sum is σ = 1291249724. Its totient is φ = 1291249722.

The previous prime is 1291249703. The next prime is 1291249763. The reversal of 1291249723 is 3279421921.

It is an a-pointer prime, because the next prime (1291249763) can be obtained adding 1291249723 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1291249723 - 2⁵ = 1291249691 is a prime.

It is not a weakly prime, because it can be changed into another prime (1291249703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645624861 + 645624862.

It is an arithmetic number, because the mean of its divisors is an integer number (645624862).

Almost surely, 2^1291249723 is an apocalyptic number.

1291249723 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291249723 is an equidigital number, since it uses as much as digits as its factorization.

1291249723 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 40.

The square root of 1291249723 is about 35933.9633633698. The cubic root of 1291249723 is about 1088.9386529415.

The spelling of 1291249723 in words is "one billion, two hundred ninety-one million, two hundred forty-nine thousand, seven hundred twenty-three".