21634720555734 has 288 divisors, whose sum is σ = 57527228959200. Its totient is φ = 5791527475200.

The previous prime is 21634720555709. The next prime is 21634720555751. The reversal of 21634720555734 is 43755502743612.

21634720555734 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 47 + 20 + 5 + 5 + 573 + 4 = 666.

It is a super-2 number, since 2×21634720555734² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 214901842 + ... + 215002490.

It is an arithmetic number, because the mean of its divisors is an integer number (199747322775).

Almost surely, 2^{21634720555734} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21634720555734, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28763614479600).

21634720555734 is an abundant number, since it is smaller than the sum of its proper divisors (35892508403466).

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

21634720555734 is a wasteful number, since it uses less digits than its factorization.

21634720555734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100816 (or 100776 counting only the distinct ones).

The product of its (nonzero) digits is 21168000, while the sum is 54.

The spelling of 21634720555734 in words is "twenty-one trillion, six hundred thirty-four billion, seven hundred twenty million, five hundred fifty-five thousand, seven hundred thirty-four".