21356143667597 has 2 divisors, whose sum is σ = 21356143667598. Its totient is φ = 21356143667596.

The previous prime is 21356143667563. The next prime is 21356143667689. The reversal of 21356143667597 is 79576634165312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19272679484356 + 2083464183241 = 4390066^2 + 1443421^2 .

It is a cyclic number.

It is not a de Polignac number, because 21356143667597 - 2¹² = 21356143663501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21356143667297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678071833798 + 10678071833799.

It is an arithmetic number, because the mean of its divisors is an integer number (10678071833799).

Almost surely, 2^{21356143667597} is an apocalyptic number.

It is an amenable number.

21356143667597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21356143667597 is an equidigital number, since it uses as much as digits as its factorization.

21356143667597 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 171460800, while the sum is 65.

The spelling of 21356143667597 in words is "twenty-one trillion, three hundred fifty-six billion, one hundred forty-three million, six hundred sixty-seven thousand, five hundred ninety-seven".