72679279931981 has 2 divisors, whose sum is σ = 72679279931982. Its totient is φ = 72679279931980.

The previous prime is 72679279931971. The next prime is 72679279932013. The reversal of 72679279931981 is 18913997297627.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51942722836900 + 20736557095081 = 7207130^2 + 4553741^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72679279931981 is a prime.

It is a super-2 number, since 2×72679279931981² (a number of 29 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 72679279931896 and 72679279931905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72679279931971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36339639965990 + 36339639965991.

It is an arithmetic number, because the mean of its divisors is an integer number (36339639965991).

Almost surely, 2^{72679279931981} is an apocalyptic number.

It is an amenable number.

72679279931981 is a deficient number, since it is larger than the sum of its proper divisors (1).

72679279931981 is an equidigital number, since it uses as much as digits as its factorization.

72679279931981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296243648, while the sum is 80.

The spelling of 72679279931981 in words is "seventy-two trillion, six hundred seventy-nine billion, two hundred seventy-nine million, nine hundred thirty-one thousand, nine hundred eighty-one".