67791028021 has 2 divisors, whose sum is σ = 67791028022. Its totient is φ = 67791028020.

The previous prime is 67791028013. The next prime is 67791028049. The reversal of 67791028021 is 12082019776.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54706871025 + 13084156996 = 233895^2 + 114386^2 .

It is a cyclic number.

It is not a de Polignac number, because 67791028021 - 2³ = 67791028013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67791068021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33895514010 + 33895514011.

It is an arithmetic number, because the mean of its divisors is an integer number (33895514011).

Almost surely, 2^67791028021 is an apocalyptic number.

It is an amenable number.

67791028021 is a deficient number, since it is larger than the sum of its proper divisors (1).

67791028021 is an equidigital number, since it uses as much as digits as its factorization.

67791028021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84672, while the sum is 43.

The spelling of 67791028021 in words is "sixty-seven billion, seven hundred ninety-one million, twenty-eight thousand, twenty-one".