21221560420631 has 4 divisors (see below), whose sum is σ = 21953338366200. Its totient is φ = 20489782475064.

The previous prime is 21221560420603. The next prime is 21221560420637. The reversal of 21221560420631 is 13602406512212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221560420631 is a prime.

It is a super-2 number, since 2×21221560420631² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21221560420591 and 21221560420600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221560420637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 365888972741 + ... + 365888972798.

It is an arithmetic number, because the mean of its divisors is an integer number (5488334591550).

Almost surely, 2^{21221560420631} is an apocalyptic number.

21221560420631 is a deficient number, since it is larger than the sum of its proper divisors (731777945569).

21221560420631 is an equidigital number, since it uses as much as digits as its factorization.

21221560420631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731777945568.

The product of its (nonzero) digits is 34560, while the sum is 35.

Adding to 21221560420631 its reverse (13602406512212), we get a palindrome (34823966932843).

The spelling of 21221560420631 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred sixty million, four hundred twenty thousand, six hundred thirty-one".