21222065720 has 32 divisors (see below), whose sum is σ = 47753835120. Its totient is φ = 8488081920.

The previous prime is 21222065687. The next prime is 21222065723. The reversal of 21222065720 is 2756022212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222065723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 787184 + ... + 813696.

Almost surely, 2^21222065720 is an apocalyptic number.

21222065720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222065720 is an abundant number, since it is smaller than the sum of its proper divisors (26531769400).

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

21222065720 is a wasteful number, since it uses less digits than its factorization.

21222065720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46535 (or 46531 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

Adding to 21222065720 its reverse (2756022212), we get a palindrome (23978087932).

The spelling of 21222065720 in words is "twenty-one billion, two hundred twenty-two million, sixty-five thousand, seven hundred twenty".