72644321 has 2 divisors, whose sum is σ = 72644322. Its totient is φ = 72644320.

The previous prime is 72644317. The next prime is 72644323. The reversal of 72644321 is 12344627.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55338721 + 17305600 = 7439^2 + 4160^2 .

It is an emirp because it is prime and its reverse (12344627) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72644321 - 2² = 72644317 is a prime.

Together with 72644323, 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 (72644323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36322160 + 36322161.

It is an arithmetic number, because the mean of its divisors is an integer number (36322161).

Almost surely, 2^72644321 is an apocalyptic number.

It is an amenable number.

72644321 is a deficient number, since it is larger than the sum of its proper divisors (1).

72644321 is an equidigital number, since it uses as much as digits as its factorization.

72644321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 29.

The square root of 72644321 is about 8523.1637905182. The cubic root of 72644321 is about 417.2540456748.

Adding to 72644321 its reverse (12344627), we get a palindrome (84988948).

The spelling of 72644321 in words is "seventy-two million, six hundred forty-four thousand, three hundred twenty-one".