21351163313566 has 16 divisors (see below), whose sum is σ = 32038306213248. Its totient is φ = 10671728250400.

The previous prime is 21351163313563. The next prime is 21351163313639. The reversal of 21351163313566 is 66531336115312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351163313563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147726576 + ... + 147871036.

It is an arithmetic number, because the mean of its divisors is an integer number (2002394138328).

Almost surely, 2^{21351163313566} is an apocalyptic number.

21351163313566 is a deficient number, since it is larger than the sum of its proper divisors (10687142899682).

21351163313566 is a wasteful number, since it uses less digits than its factorization.

21351163313566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170627.

The product of its digits is 874800, while the sum is 46.

Adding to 21351163313566 its reverse (66531336115312), we get a palindrome (87882499428878).

The spelling of 21351163313566 in words is "twenty-one trillion, three hundred fifty-one billion, one hundred sixty-three million, three hundred thirteen thousand, five hundred sixty-six".