20921944648 has 32 divisors (see below), whose sum is σ = 42804313920. Its totient is φ = 9507880000.

The previous prime is 20921944633. The next prime is 20921944649. The reversal of 20921944648 is 84644912902.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20921944649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 418173 + ... + 465523.

It is an arithmetic number, because the mean of its divisors is an integer number (1337634810).

Almost surely, 2^20921944648 is an apocalyptic number.

It is an amenable number.

20921944648 is an abundant number, since it is smaller than the sum of its proper divisors (21882369272).

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

20921944648 is a wasteful number, since it uses less digits than its factorization.

20921944648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52389 (or 52385 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 49.

It can be divided in two parts, 20921 and 944648, that added together give a palindrome (965569).

The spelling of 20921944648 in words is "twenty billion, nine hundred twenty-one million, nine hundred forty-four thousand, six hundred forty-eight".