7231972721 has 2 divisors, whose sum is σ = 7231972722. Its totient is φ = 7231972720.

The previous prime is 7231972691. The next prime is 7231972723. The reversal of 7231972721 is 1272791327.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6108985600 + 1122987121 = 78160^2 + 33511^2 .

It is an emirp because it is prime and its reverse (1272791327) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7231972721 - 2¹⁰ = 7231971697 is a prime.

Together with 7231972723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (7231972723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3615986360 + 3615986361.

It is an arithmetic number, because the mean of its divisors is an integer number (3615986361).

Almost surely, 2^7231972721 is an apocalyptic number.

It is an amenable number.

7231972721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7231972721 is an equidigital number, since it uses as much as digits as its factorization.

7231972721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 74088, while the sum is 41.

The square root of 7231972721 is about 85041.0061146974. The cubic root of 7231972721 is about 1933.8328193753.

The spelling of 7231972721 in words is "seven billion, two hundred thirty-one million, nine hundred seventy-two thousand, seven hundred twenty-one".