1305721648 has 160 divisors (see below), whose sum is σ = 3354785280. Its totient is φ = 480902400.

The previous prime is 1305721639. The next prime is 1305721657. The reversal of 1305721648 is 8461275031.

It is an interprime number because it is at equal distance from previous prime (1305721639) and next prime (1305721657).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 2832138 + ... + 2832598.

It is an arithmetic number, because the mean of its divisors is an integer number (20967408).

Almost surely, 2^1305721648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1305721648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1677392640).

1305721648 is an abundant number, since it is smaller than the sum of its proper divisors (2049063632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1305721648 is a wasteful number, since it uses less digits than its factorization.

1305721648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 1305721648 is about 36134.7706233207. The cubic root of 1305721648 is about 1092.9917104730.

Adding to 1305721648 its reverse (8461275031), we get a palindrome (9766996679).

The spelling of 1305721648 in words is "one billion, three hundred five million, seven hundred twenty-one thousand, six hundred forty-eight".