72821324861 has 2 divisors, whose sum is σ = 72821324862. Its totient is φ = 72821324860.

The previous prime is 72821324813. The next prime is 72821324879. The reversal of 72821324861 is 16842312827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67635884761 + 5185440100 = 260069^2 + 72010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72821324861 is a prime.

It is a super-2 number, since 2×72821324861² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72821324801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36410662430 + 36410662431.

It is an arithmetic number, because the mean of its divisors is an integer number (36410662431).

Almost surely, 2^72821324861 is an apocalyptic number.

It is an amenable number.

72821324861 is a deficient number, since it is larger than the sum of its proper divisors (1).

72821324861 is an equidigital number, since it uses as much as digits as its factorization.

72821324861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 44.

The spelling of 72821324861 in words is "seventy-two billion, eight hundred twenty-one million, three hundred twenty-four thousand, eight hundred sixty-one".