42779976721 has 2 divisors, whose sum is σ = 42779976722. Its totient is φ = 42779976720.

The previous prime is 42779976713. The next prime is 42779976727. The reversal of 42779976721 is 12767997724.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23928686721 + 18851290000 = 154689^2 + 137300^2 .

It is a cyclic number.

It is not a de Polignac number, because 42779976721 - 2³ = 42779976713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42779976721.

It is not a weakly prime, because it can be changed into another prime (42779976727) 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, 21389988360 + 21389988361.

It is an arithmetic number, because the mean of its divisors is an integer number (21389988361).

Almost surely, 2^42779976721 is an apocalyptic number.

It is an amenable number.

42779976721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42779976721 is an equidigital number, since it uses as much as digits as its factorization.

42779976721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18670176, while the sum is 61.

The spelling of 42779976721 in words is "forty-two billion, seven hundred seventy-nine million, nine hundred seventy-six thousand, seven hundred twenty-one".