78933552721 has 2 divisors, whose sum is σ = 78933552722. Its totient is φ = 78933552720.

The previous prime is 78933552701. The next prime is 78933552767. The reversal of 78933552721 is 12725533987.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64585106496 + 14348446225 = 254136^2 + 119785^2 .

It is a cyclic number.

It is not a de Polignac number, because 78933552721 - 2²¹ = 78931455569 is a prime.

It is not a weakly prime, because it can be changed into another prime (78933552701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39466776360 + 39466776361.

It is an arithmetic number, because the mean of its divisors is an integer number (39466776361).

Almost surely, 2^78933552721 is an apocalyptic number.

It is an amenable number.

78933552721 is a deficient number, since it is larger than the sum of its proper divisors (1).

78933552721 is an equidigital number, since it uses as much as digits as its factorization.

78933552721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3175200, while the sum is 52.

The spelling of 78933552721 in words is "seventy-eight billion, nine hundred thirty-three million, five hundred fifty-two thousand, seven hundred twenty-one".