21700738944640 has 640 divisors, whose sum is σ = 61600551062400. Its totient is φ = 7308663054336.

The previous prime is 21700738944623. The next prime is 21700738944653. The reversal of 21700738944640 is 4644983700712.

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 29206916109 + ... + 29206916851.

It is an arithmetic number, because the mean of its divisors is an integer number (96250861035).

Almost surely, 2^{21700738944640} is an apocalyptic number.

21700738944640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21700738944640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30800275531200).

21700738944640 is an abundant number, since it is smaller than the sum of its proper divisors (39899812117760).

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

21700738944640 is an frugal number, since it uses more digits than its factorization.

21700738944640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1102 (or 1069 counting only the distinct ones).

The product of its (nonzero) digits is 8128512, while the sum is 55.

The spelling of 21700738944640 in words is "twenty-one trillion, seven hundred billion, seven hundred thirty-eight million, nine hundred forty-four thousand, six hundred forty".