28666639669 has 2 divisors, whose sum is σ = 28666639670. Its totient is φ = 28666639668.

The previous prime is 28666639643. The next prime is 28666639679. The reversal of 28666639669 is 96693666682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28301332900 + 365306769 = 168230^2 + 19113^2 .

It is a cyclic number.

It is not a de Polignac number, because 28666639669 - 2⁵ = 28666639637 is a prime.

It is a super-2 number, since 2×28666639669² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28666639679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14333319834 + 14333319835.

It is an arithmetic number, because the mean of its divisors is an integer number (14333319835).

Almost surely, 2^28666639669 is an apocalyptic number.

It is an amenable number.

28666639669 is a deficient number, since it is larger than the sum of its proper divisors (1).

28666639669 is an equidigital number, since it uses as much as digits as its factorization.

28666639669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181398528, while the sum is 67.

The spelling of 28666639669 in words is "twenty-eight billion, six hundred sixty-six million, six hundred thirty-nine thousand, six hundred sixty-nine".