21115655213533 has 2 divisors, whose sum is σ = 21115655213534. Its totient is φ = 21115655213532.

The previous prime is 21115655213519. The next prime is 21115655213617. The reversal of 21115655213533 is 33531255651112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18628089064729 + 2487566148804 = 4316027^2 + 1577202^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115655213533 - 2²⁹ = 21115118342621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21115655213533.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115655213033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557827606766 + 10557827606767.

It is an arithmetic number, because the mean of its divisors is an integer number (10557827606767).

Almost surely, 2^{21115655213533} is an apocalyptic number.

It is an amenable number.

21115655213533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115655213533 is an equidigital number, since it uses as much as digits as its factorization.

21115655213533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 405000, while the sum is 43.

The spelling of 21115655213533 in words is "twenty-one trillion, one hundred fifteen billion, six hundred fifty-five million, two hundred thirteen thousand, five hundred thirty-three".