216117720 has 320 divisors, whose sum is σ = 895245120. Its totient is φ = 45536256.

The previous prime is 216117701. The next prime is 216117743. The reversal of 216117720 is 27711612.

216117720 is a `hidden beast` number, since 21 + 611 + 7 + 7 + 20 = 666.

216117720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 294474 + ... + 295206.

It is an arithmetic number, because the mean of its divisors is an integer number (2797641).

Almost surely, 2^216117720 is an apocalyptic number.

216117720 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 216117720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (447622560).

216117720 is an abundant number, since it is smaller than the sum of its proper divisors (679127400).

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

216117720 is a wasteful number, since it uses less digits than its factorization.

216117720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 776 (or 763 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

The square root of 216117720 is about 14700.9428269074. The cubic root of 216117720 is about 600.1089802043.

It can be divided in two parts, 2161 and 17720, that added together give a square (19881 = 141²).

The spelling of 216117720 in words is "two hundred sixteen million, one hundred seventeen thousand, seven hundred twenty".