7291281321 has 9 divisors (see below), whose sum is σ = 10532220829. Its totient is φ = 4860683436.

The previous prime is 7291281311. The next prime is 7291281323. The reversal of 7291281321 is 1231821927.

The square root of 7291281321 is 85389.

It is a perfect power (a square), and thus also a powerful number.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 7291281321 - 2⁹ = 7291280809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7291281323) 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 in 8 ways as a sum of consecutive naturals, for example, 241936 + ... + 270398.

Almost surely, 2^7291281321 is an apocalyptic number.

7291281321 is the 85389-th square number.

7291281321 is the 42695-th centered octagonal number.

It is an amenable number.

7291281321 is a deficient number, since it is larger than the sum of its proper divisors (3240939508).

7291281321 is an frugal number, since it uses more digits than its factorization.

7291281321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56932 (or 28466 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The cubic root of 7291281321 is about 1939.1048161190.

Multiplying 7291281321 by its sum of digits (36), we get a square (262486127556 = 512334²).

The spelling of 7291281321 in words is "seven billion, two hundred ninety-one million, two hundred eighty-one thousand, three hundred twenty-one".