21016716512 has 72 divisors (see below), whose sum is σ = 46159508808. Its totient is φ = 9410353920.

The previous prime is 21016716491. The next prime is 21016716547. The reversal of 21016716512 is 21561761012.

It is a super-2 number, since 2×21016716512² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 218918 + ... + 299930.

It is an arithmetic number, because the mean of its divisors is an integer number (641104289).

Almost surely, 2^21016716512 is an apocalyptic number.

21016716512 is a gapful number since it is divisible by the number (22) 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 21016716512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23079754404).

21016716512 is an abundant number, since it is smaller than the sum of its proper divisors (25142792296).

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

21016716512 is a wasteful number, since it uses less digits than its factorization.

21016716512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81112 (or 81093 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The spelling of 21016716512 in words is "twenty-one billion, sixteen million, seven hundred sixteen thousand, five hundred twelve".