21616231664669 has 2 divisors, whose sum is σ = 21616231664670. Its totient is φ = 21616231664668.

The previous prime is 21616231664647. The next prime is 21616231664693. The reversal of 21616231664669 is 96646613261612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19723928792569 + 1892302872100 = 4441163^2 + 1375610^2 .

It is a cyclic number.

It is not a de Polignac number, because 21616231664669 - 2⁸ = 21616231664413 is a prime.

It is a super-2 number, since 2×21616231664669² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21616231664369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808115832334 + 10808115832335.

It is an arithmetic number, because the mean of its divisors is an integer number (10808115832335).

Almost surely, 2^{21616231664669} is an apocalyptic number.

It is an amenable number.

21616231664669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616231664669 is an equidigital number, since it uses as much as digits as its factorization.

21616231664669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20155392, while the sum is 59.

The spelling of 21616231664669 in words is "twenty-one trillion, six hundred sixteen billion, two hundred thirty-one million, six hundred sixty-four thousand, six hundred sixty-nine".