21008844660 has 48 divisors (see below), whose sum is σ = 59273831232. Its totient is φ = 5559590400.

The previous prime is 21008844653. The next prime is 21008844707. The reversal of 21008844660 is 6644880012.

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 15 ways as a sum of consecutive naturals, for example, 1328581 + ... + 1344300.

It is an arithmetic number, because the mean of its divisors is an integer number (1234871484).

Almost surely, 2^21008844660 is an apocalyptic number.

21008844660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21008844660 is an abundant number, since it is smaller than the sum of its proper divisors (38264986572).

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

21008844660 is a wasteful number, since it uses less digits than its factorization.

21008844660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2673024 (or 2673022 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 39.

The spelling of 21008844660 in words is "twenty-one billion, eight million, eight hundred forty-four thousand, six hundred sixty".