21815063216077 has 2 divisors, whose sum is σ = 21815063216078. Its totient is φ = 21815063216076.

The previous prime is 21815063216041. The next prime is 21815063216129. The reversal of 21815063216077 is 77061236051812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20166152974276 + 1648910241801 = 4490674^2 + 1284099^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21815063216077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21815063216077.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21815063219077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10907531608038 + 10907531608039.

It is an arithmetic number, because the mean of its divisors is an integer number (10907531608039).

Almost surely, 2^{21815063216077} is an apocalyptic number.

It is an amenable number.

21815063216077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21815063216077 is an equidigital number, since it uses as much as digits as its factorization.

21815063216077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 846720, while the sum is 49.

Adding to 21815063216077 its reverse (77061236051812), we get a palindrome (98876299267889).

The spelling of 21815063216077 in words is "twenty-one trillion, eight hundred fifteen billion, sixty-three million, two hundred sixteen thousand, seventy-seven".