21616543353497 has 2 divisors, whose sum is σ = 21616543353498. Its totient is φ = 21616543353496.

The previous prime is 21616543353491. The next prime is 21616543353571. The reversal of 21616543353497 is 79435334561612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21417541712281 + 199001641216 = 4627909^2 + 446096^2 .

It is a cyclic number.

It is not a de Polignac number, because 21616543353497 - 2⁴ = 21616543353481 is a prime.

It is not a weakly prime, because it can be changed into another prime (21616543353491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808271676748 + 10808271676749.

It is an arithmetic number, because the mean of its divisors is an integer number (10808271676749).

Almost surely, 2^{21616543353497} is an apocalyptic number.

It is an amenable number.

21616543353497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616543353497 is an equidigital number, since it uses as much as digits as its factorization.

21616543353497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48988800, while the sum is 59.

The spelling of 21616543353497 in words is "twenty-one trillion, six hundred sixteen billion, five hundred forty-three million, three hundred fifty-three thousand, four hundred ninety-seven".