1244721649 has 4 divisors (see below), whose sum is σ = 1250064036. Its totient is φ = 1239379264.

The previous prime is 1244721631. The next prime is 1244721671. The reversal of 1244721649 is 9461274421.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9461274421 = 227 ⋅41679623.

It can be written as a sum of positive squares in 2 ways, for example, as 512207424 + 732514225 = 22632^2 + 27065^2 .

It is a cyclic number.

It is not a de Polignac number, because 1244721649 - 2¹¹ = 1244719601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1244721619) 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, 2670844 + ... + 2671309.

It is an arithmetic number, because the mean of its divisors is an integer number (312516009).

Almost surely, 2^1244721649 is an apocalyptic number.

It is an amenable number.

1244721649 is a deficient number, since it is larger than the sum of its proper divisors (5342387).

1244721649 is an equidigital number, since it uses as much as digits as its factorization.

1244721649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5342386.

The product of its digits is 96768, while the sum is 40.

The square root of 1244721649 is about 35280.6129340180. The cubic root of 1244721649 is about 1075.6989574508.

The spelling of 1244721649 in words is "one billion, two hundred forty-four million, seven hundred twenty-one thousand, six hundred forty-nine".