216566761720 has 64 divisors (see below), whose sum is σ = 498575088000. Its totient is φ = 84635860608.

The previous prime is 216566761693. The next prime is 216566761721. The reversal of 216566761720 is 27167665612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216566761721) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 103191 + ... + 666169.

It is an arithmetic number, because the mean of its divisors is an integer number (7790235750).

Almost surely, 2^216566761720 is an apocalyptic number.

216566761720 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 216566761720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249287544000).

216566761720 is an abundant number, since it is smaller than the sum of its proper divisors (282008326280).

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

216566761720 is a wasteful number, since it uses less digits than its factorization.

216566761720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563212 (or 563208 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 49.

The spelling of 216566761720 in words is "two hundred sixteen billion, five hundred sixty-six million, seven hundred sixty-one thousand, seven hundred twenty".