67668707021 has 4 divisors (see below), whose sum is σ = 68945475132. Its totient is φ = 66391938912.

The previous prime is 67668707017. The next prime is 67668707047. The reversal of 67668707021 is 12070786676.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19996788100 + 47671918921 = 141410^2 + 218339^2 .

It is a cyclic number.

It is not a de Polignac number, because 67668707021 - 2² = 67668707017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67668701021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 638383976 + ... + 638384081.

It is an arithmetic number, because the mean of its divisors is an integer number (17236368783).

Almost surely, 2^67668707021 is an apocalyptic number.

It is an amenable number.

67668707021 is a deficient number, since it is larger than the sum of its proper divisors (1276768111).

67668707021 is a wasteful number, since it uses less digits than its factorization.

67668707021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276768110.

The product of its (nonzero) digits is 1185408, while the sum is 50.

The spelling of 67668707021 in words is "sixty-seven billion, six hundred sixty-eight million, seven hundred seven thousand, twenty-one".