21071616016660 has 96 divisors (see below), whose sum is σ = 48763289457792. Its totient is φ = 7584923934720.

The previous prime is 21071616016643. The next prime is 21071616016741. The reversal of 21071616016660 is 6661061617012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9649159 + ... + 11629681.

It is an arithmetic number, because the mean of its divisors is an integer number (507950931852).

Almost surely, 2^{21071616016660} is an apocalyptic number.

21071616016660 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 21071616016660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24381644728896).

21071616016660 is an abundant number, since it is smaller than the sum of its proper divisors (27691673441132).

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

21071616016660 is a wasteful number, since it uses less digits than its factorization.

21071616016660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1981033 (or 1981031 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 43.

The spelling of 21071616016660 in words is "twenty-one trillion, seventy-one billion, six hundred sixteen million, sixteen thousand, six hundred sixty".