16781215664466 has 96 divisors (see below), whose sum is σ = 40129221787200. Its totient is φ = 5025715453440.

The previous prime is 16781215664449. The next prime is 16781215664467. The reversal of 16781215664466 is 66446651218761.

16781215664466 is a `hidden beast` number, since 1 + 6 + 7 + 8 + 1 + 2 + 1 + 566 + 4 + 4 + 66 = 666.

It is not an unprimeable number, because it can be changed into a prime (16781215664467) 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, 37435405 + ... + 37881023.

It is an arithmetic number, because the mean of its divisors is an integer number (418012726950).

Almost surely, 2^{16781215664466} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16781215664466, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20064610893600).

16781215664466 is an abundant number, since it is smaller than the sum of its proper divisors (23348006122734).

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

16781215664466 is a wasteful number, since it uses less digits than its factorization.

16781215664466 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447864 (or 447861 counting only the distinct ones).

The product of its digits is 69672960, while the sum is 63.

The spelling of 16781215664466 in words is "sixteen trillion, seven hundred eighty-one billion, two hundred fifteen million, six hundred sixty-four thousand, four hundred sixty-six".