21720350548 has 12 divisors (see below), whose sum is σ = 40934506900. Its totient is φ = 10024777152.

The previous prime is 21720350521. The next prime is 21720350551. The reversal of 21720350548 is 84505302712.

It can be written as a sum of positive squares in 2 ways, for example, as 3072263184 + 18648087364 = 55428^2 + 136558^2 .

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 208849473 + ... + 208849576.

Almost surely, 2^21720350548 is an apocalyptic number.

It is an amenable number.

21720350548 is a deficient number, since it is larger than the sum of its proper divisors (19214156352).

21720350548 is a wasteful number, since it uses less digits than its factorization.

21720350548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417699066 (or 417699064 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 37.

The spelling of 21720350548 in words is "twenty-one billion, seven hundred twenty million, three hundred fifty thousand, five hundred forty-eight".