216711781377 has 48 divisors (see below), whose sum is σ = 359160192000. Its totient is φ = 113805521856.

The previous prime is 216711781373. The next prime is 216711781379. The reversal of 216711781377 is 773187117612.

It is a happy number.

It is not a de Polignac number, because 216711781377 - 2² = 216711781373 is a prime.

It is a super-2 number, since 2×216711781377² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (216711781373) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 671124 + ... + 940122.

It is an arithmetic number, because the mean of its divisors is an integer number (7482504000).

Almost surely, 2^216711781377 is an apocalyptic number.

It is an amenable number.

216711781377 is a deficient number, since it is larger than the sum of its proper divisors (142448410623).

216711781377 is a wasteful number, since it uses less digits than its factorization.

216711781377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269262 (or 269249 counting only the distinct ones).

The product of its digits is 691488, while the sum is 51.

Adding to 216711781377 its reverse (773187117612), we get a palindrome (989898898989).

The spelling of 216711781377 in words is "two hundred sixteen billion, seven hundred eleven million, seven hundred eighty-one thousand, three hundred seventy-seven".