79673981 has 2 divisors, whose sum is σ = 79673982. Its totient is φ = 79673980.

The previous prime is 79673959. The next prime is 79673983. The reversal of 79673981 is 18937697.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79049881 + 624100 = 8891^2 + 790^2 .

It is an emirp because it is prime and its reverse (18937697) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79673981 - 2¹⁸ = 79411837 is a prime.

It is a super-2 number, since 2×79673981² = 12695886496776722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 79673983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79673983) 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, 39836990 + 39836991.

It is an arithmetic number, because the mean of its divisors is an integer number (39836991).

Almost surely, 2^79673981 is an apocalyptic number.

It is an amenable number.

79673981 is a deficient number, since it is larger than the sum of its proper divisors (1).

79673981 is an equidigital number, since it uses as much as digits as its factorization.

79673981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 571536, while the sum is 50.

The square root of 79673981 is about 8926.0282881022. The cubic root of 79673981 is about 430.3008188897.

The spelling of 79673981 in words is "seventy-nine million, six hundred seventy-three thousand, nine hundred eighty-one".