21556124216 has 32 divisors (see below), whose sum is σ = 46009123200. Its totient is φ = 9372227040.

The previous prime is 21556124209. The next prime is 21556124267. The reversal of 21556124216 is 61242165512.

It is a super-2 number, since 2×21556124216² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5323106 + ... + 5327153.

It is an arithmetic number, because the mean of its divisors is an integer number (1437785100).

Almost surely, 2^21556124216 is an apocalyptic number.

It is an amenable number.

21556124216 is an abundant number, since it is smaller than the sum of its proper divisors (24452998984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21556124216 is a wasteful number, since it uses less digits than its factorization.

21556124216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10650299 (or 10650295 counting only the distinct ones).

The product of its digits is 28800, while the sum is 35.

Adding to 21556124216 its reverse (61242165512), we get a palindrome (82798289728).

The spelling of 21556124216 in words is "twenty-one billion, five hundred fifty-six million, one hundred twenty-four thousand, two hundred sixteen".