73231721 has 2 divisors, whose sum is σ = 73231722. Its totient is φ = 73231720.

The previous prime is 73231693. The next prime is 73231723. The reversal of 73231721 is 12713237.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37650496 + 35581225 = 6136^2 + 5965^2 .

It is a cyclic number.

It is not a de Polignac number, because 73231721 - 2¹⁰ = 73230697 is a prime.

Together with 73231723, 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 (73231723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36615860 + 36615861.

It is an arithmetic number, because the mean of its divisors is an integer number (36615861).

Almost surely, 2^73231721 is an apocalyptic number.

It is an amenable number.

73231721 is a deficient number, since it is larger than the sum of its proper divisors (1).

73231721 is an equidigital number, since it uses as much as digits as its factorization.

73231721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1764, while the sum is 26.

The square root of 73231721 is about 8557.5534471016. The cubic root of 73231721 is about 418.3756629107.

Adding to 73231721 its reverse (12713237), we get a palindrome (85944958).

The spelling of 73231721 in words is "seventy-three million, two hundred thirty-one thousand, seven hundred twenty-one".