21500553504534 has 96 divisors (see below), whose sum is σ = 49061616019200. Its totient is φ = 6261283117440.

The previous prime is 21500553504473. The next prime is 21500553504581. The reversal of 21500553504534 is 43540535500512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19322032 + ... + 20404460.

It is an arithmetic number, because the mean of its divisors is an integer number (511058500200).

Almost surely, 2^{21500553504534} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21500553504534, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24530808009600).

21500553504534 is an abundant number, since it is smaller than the sum of its proper divisors (27561062514666).

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

21500553504534 is a wasteful number, since it uses less digits than its factorization.

21500553504534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083510 (or 1083497 counting only the distinct ones).

The product of its (nonzero) digits is 900000, while the sum is 42.

The spelling of 21500553504534 in words is "twenty-one trillion, five hundred billion, five hundred fifty-three million, five hundred four thousand, five hundred thirty-four".