72821326309 has 2 divisors, whose sum is σ = 72821326310. Its totient is φ = 72821326308.

The previous prime is 72821326247. The next prime is 72821326343. The reversal of 72821326309 is 90362312827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69737190084 + 3084136225 = 264078^2 + 55535^2 .

It is a cyclic number.

It is not a de Polignac number, because 72821326309 - 2²⁵ = 72787771877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72821326379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36410663154 + 36410663155.

It is an arithmetic number, because the mean of its divisors is an integer number (36410663155).

Almost surely, 2^72821326309 is an apocalyptic number.

It is an amenable number.

72821326309 is a deficient number, since it is larger than the sum of its proper divisors (1).

72821326309 is an equidigital number, since it uses as much as digits as its factorization.

72821326309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 217728, while the sum is 43.

The spelling of 72821326309 in words is "seventy-two billion, eight hundred twenty-one million, three hundred twenty-six thousand, three hundred nine".