21015543310455 has 32 divisors (see below), whose sum is σ = 33828914566656. Its totient is φ = 11140467089024.

The previous prime is 21015543310439. The next prime is 21015543310457. The reversal of 21015543310455 is 55401334551012.

It is a cyclic number.

It is not a de Polignac number, because 21015543310455 - 2⁴ = 21015543310439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21015543310457) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4264932 + ... + 7760201.

It is an arithmetic number, because the mean of its divisors is an integer number (1057153580208).

Almost surely, 2^{21015543310455} is an apocalyptic number.

21015543310455 is a deficient number, since it is larger than the sum of its proper divisors (12813371256201).

21015543310455 is a wasteful number, since it uses less digits than its factorization.

21015543310455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12025847.

The product of its (nonzero) digits is 180000, while the sum is 39.

Adding to 21015543310455 its reverse (55401334551012), we get a palindrome (76416877861467).

The spelling of 21015543310455 in words is "twenty-one trillion, fifteen billion, five hundred forty-three million, three hundred ten thousand, four hundred fifty-five".