21720350552 has 32 divisors (see below), whose sum is σ = 40896262800. Its totient is φ = 10814753664.

The previous prime is 21720350551. The next prime is 21720350563. The reversal of 21720350552 is 25505302712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21720350551) 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, 2808563 + ... + 2816285.

Almost surely, 2^21720350552 is an apocalyptic number.

It is an amenable number.

21720350552 is a deficient number, since it is larger than the sum of its proper divisors (19175912248).

21720350552 is a wasteful number, since it uses less digits than its factorization.

21720350552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9155 (or 9151 counting only the distinct ones).

The product of its (nonzero) digits is 21000, while the sum is 32.

The spelling of 21720350552 in words is "twenty-one billion, seven hundred twenty million, three hundred fifty thousand, five hundred fifty-two".