21138882071616 has 105 divisors (see below), whose sum is σ = 62663249977669. Its totient is φ = 7046183678976.

The previous prime is 21138882071569. The next prime is 21138882071617. The reversal of 21138882071616 is 61617028883112.

The square root of 21138882071616 is 4597704.

It is a perfect power (a square), and thus also a powerful number.

21138882071616 is a `hidden beast` number, since 2 + 1 + 13 + 8 + 8 + 8 + 2 + 0 + 7 + 1 + 616 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14182454721600 + 6956427350016 = 3765960^2 + 2637504^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21138882071617) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 331002760 + ... + 331066616.

Almost surely, 2^{21138882071616} is an apocalyptic number.

21138882071616 is the 4597704-th square number.

It is an amenable number.

21138882071616 is an abundant number, since it is smaller than the sum of its proper divisors (41524367906053).

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

21138882071616 is an frugal number, since it uses more digits than its factorization.

21138882071616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127738 (or 63862 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 21138882071616 in words is "twenty-one trillion, one hundred thirty-eight billion, eight hundred eighty-two million, seventy-one thousand, six hundred sixteen".