21730555908 has 72 divisors (see below), whose sum is σ = 57120615552. Its totient is φ = 7223662944.

The previous prime is 21730555907. The next prime is 21730555933. The reversal of 21730555908 is 80955503712.

21730555908 is a `hidden beast` number, since 2 + 1 + 7 + 3 + 0 + 55 + 590 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (21730555901) 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 23 ways as a sum of consecutive naturals, for example, 326266 + ... + 387182.

Almost surely, 2^21730555908 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21730555908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28560307776).

21730555908 is an abundant number, since it is smaller than the sum of its proper divisors (35390059644).

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

21730555908 is a wasteful number, since it uses less digits than its factorization.

21730555908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61303 (or 61289 counting only the distinct ones).

The product of its (nonzero) digits is 378000, while the sum is 45.

The spelling of 21730555908 in words is "twenty-one billion, seven hundred thirty million, five hundred fifty-five thousand, nine hundred eight".