21724156216 has 64 divisors (see below), whose sum is σ = 46898542080. Its totient is φ = 9241153920.

The previous prime is 21724156193. The next prime is 21724156261. The reversal of 21724156216 is 61265142712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12477106 + ... + 12478846.

It is an arithmetic number, because the mean of its divisors is an integer number (732789720).

Almost surely, 2^21724156216 is an apocalyptic number.

It is an amenable number.

21724156216 is an abundant number, since it is smaller than the sum of its proper divisors (25174385864).

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

21724156216 is a wasteful number, since it uses less digits than its factorization.

21724156216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3284 (or 3280 counting only the distinct ones).

The product of its digits is 40320, while the sum is 37.

Adding to 21724156216 its reverse (61265142712), we get a palindrome (82989298928).

The spelling of 21724156216 in words is "twenty-one billion, seven hundred twenty-four million, one hundred fifty-six thousand, two hundred sixteen".