21620734205063 has 16 divisors (see below), whose sum is σ = 25506887546880. Its totient is φ = 17933968836000.

The previous prime is 21620734205039. The next prime is 21620734205087. The reversal of 21620734205063 is 36050243702612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21620734205039) and next prime (21620734205087).

It is not a de Polignac number, because 21620734205063 - 2¹⁸ = 21620733942919 is a prime.

It is a super-2 number, since 2×21620734205063² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21620734205063.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620734205033) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13735913 + ... + 15228813.

It is an arithmetic number, because the mean of its divisors is an integer number (1594180471680).

Almost surely, 2^{21620734205063} is an apocalyptic number.

21620734205063 is a deficient number, since it is larger than the sum of its proper divisors (3886153341817).

21620734205063 is a wasteful number, since it uses less digits than its factorization.

21620734205063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1559678.

The product of its (nonzero) digits is 362880, while the sum is 41.

Adding to 21620734205063 its reverse (36050243702612), we get a palindrome (57670977907675).

The spelling of 21620734205063 in words is "twenty-one trillion, six hundred twenty billion, seven hundred thirty-four million, two hundred five thousand, sixty-three".