67693639681 has 2 divisors, whose sum is σ = 67693639682. Its totient is φ = 67693639680.

The previous prime is 67693639661. The next prime is 67693639691. The reversal of 67693639681 is 18693639676.

67693639681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62910672400 + 4782967281 = 250820^2 + 69159^2 .

It is a cyclic number.

It is not a de Polignac number, because 67693639681 - 2¹⁵ = 67693606913 is a prime.

It is a super-2 number, since 2×67693639681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (67693639661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33846819840 + 33846819841.

It is an arithmetic number, because the mean of its divisors is an integer number (33846819841).

Almost surely, 2^67693639681 is an apocalyptic number.

It is an amenable number.

67693639681 is a deficient number, since it is larger than the sum of its proper divisors (1).

67693639681 is an equidigital number, since it uses as much as digits as its factorization.

67693639681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52907904, while the sum is 64.

It can be divided in two parts, 676936 and 39681, that added together give a palindrome (716617).

The spelling of 67693639681 in words is "sixty-seven billion, six hundred ninety-three million, six hundred thirty-nine thousand, six hundred eighty-one".