1681447895666 has 16 divisors (see below), whose sum is σ = 3144525935040. Its totient is φ = 655109569680.

The previous prime is 1681447895663. The next prime is 1681447895693. The reversal of 1681447895666 is 6665987441861.

It is a self number, because there is not a number n which added to its sum of digits gives 1681447895666.

It is not an unprimeable number, because it can be changed into a prime (1681447895663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5459246261 + ... + 5459246568.

It is an arithmetic number, because the mean of its divisors is an integer number (196532870940).

Almost surely, 2^{1681447895666} is an apocalyptic number.

1681447895666 is a deficient number, since it is larger than the sum of its proper divisors (1463078039374).

1681447895666 is a wasteful number, since it uses less digits than its factorization.

1681447895666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10918492849.

The product of its digits is 418037760, while the sum is 71.

The spelling of 1681447895666 in words is "one trillion, six hundred eighty-one billion, four hundred forty-seven million, eight hundred ninety-five thousand, six hundred sixty-six".