21123451334666 has 8 divisors (see below), whose sum is σ = 31793317538724. Its totient is φ = 10525678821760.

The previous prime is 21123451334653. The next prime is 21123451334749. The reversal of 21123451334666 is 66643315432112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19880496150025 + 1242955184641 = 4458755^2 + 1114879^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21123451334666.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 18023422055 + ... + 18023423226.

Almost surely, 2^{21123451334666} is an apocalyptic number.

21123451334666 is a deficient number, since it is larger than the sum of its proper divisors (10669866204058).

21123451334666 is a wasteful number, since it uses less digits than its factorization.

21123451334666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36046845576.

The product of its digits is 1866240, while the sum is 47.

Adding to 21123451334666 its reverse (66643315432112), we get a palindrome (87766766766778).

The spelling of 21123451334666 in words is "twenty-one trillion, one hundred twenty-three billion, four hundred fifty-one million, three hundred thirty-four thousand, six hundred sixty-six".