16581644946 has 96 divisors (see below), whose sum is σ = 37988478528. Its totient is φ = 5419560960.

The previous prime is 16581644941. The next prime is 16581644953. The reversal of 16581644946 is 64944618561.

16581644946 is a `hidden beast` number, since 16 + 5 + 81 + 64 + 494 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16581644892 and 16581644901.

It is not an unprimeable number, because it can be changed into a prime (16581644941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7846386 + ... + 7848498.

It is an arithmetic number, because the mean of its divisors is an integer number (395713318).

Almost surely, 2^16581644946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16581644946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18994239264).

16581644946 is an abundant number, since it is smaller than the sum of its proper divisors (21406833582).

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

16581644946 is a wasteful number, since it uses less digits than its factorization.

16581644946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2438 (or 2426 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 54.

The spelling of 16581644946 in words is "sixteen billion, five hundred eighty-one million, six hundred forty-four thousand, nine hundred forty-six".