215781111216 has 240 divisors, whose sum is σ = 683821232640. Its totient is φ = 65327420160.

The previous prime is 215781111199. The next prime is 215781111223. The reversal of 215781111216 is 612111187512.

It is a happy number.

It is a super-2 number, since 2×215781111216² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 71378281 + ... + 71381303.

It is an arithmetic number, because the mean of its divisors is an integer number (2849255136).

Almost surely, 2^215781111216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215781111216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (341910616320).

215781111216 is an abundant number, since it is smaller than the sum of its proper divisors (468040121424).

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

215781111216 is a wasteful number, since it uses less digits than its factorization.

215781111216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4726 (or 4708 counting only the distinct ones).

The product of its digits is 6720, while the sum is 36.

Adding to 215781111216 its reverse (612111187512), we get a palindrome (827892298728).

The spelling of 215781111216 in words is "two hundred fifteen billion, seven hundred eighty-one million, one hundred eleven thousand, two hundred sixteen".