21539618376 has 128 divisors (see below), whose sum is σ = 56142720000. Its totient is φ = 6880591872.

The previous prime is 21539618323. The next prime is 21539618389. The reversal of 21539618376 is 67381693512.

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 31 ways as a sum of consecutive naturals, for example, 35485065 + ... + 35485671.

It is an arithmetic number, because the mean of its divisors is an integer number (438615000).

Almost surely, 2^21539618376 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21539618376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28071360000).

21539618376 is an abundant number, since it is smaller than the sum of its proper divisors (34603101624).

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

21539618376 is a wasteful number, since it uses less digits than its factorization.

21539618376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1191 (or 1187 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 51.

The spelling of 21539618376 in words is "twenty-one billion, five hundred thirty-nine million, six hundred eighteen thousand, three hundred seventy-six".