16666462626421 has 2 divisors, whose sum is σ = 16666462626422. Its totient is φ = 16666462626420.

The previous prime is 16666462626419. The next prime is 16666462626467. The reversal of 16666462626421 is 12462626466661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16105332791025 + 561129835396 = 4013145^2 + 749086^2 .

It is a cyclic number.

It is not a de Polignac number, because 16666462626421 - 2¹ = 16666462626419 is a prime.

Together with 16666462626419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16666462626221) 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 as a sum of consecutive naturals, namely, 8333231313210 + 8333231313211.

It is an arithmetic number, because the mean of its divisors is an integer number (8333231313211).

Almost surely, 2^{16666462626421} is an apocalyptic number.

It is an amenable number.

16666462626421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16666462626421 is an equidigital number, since it uses as much as digits as its factorization.

16666462626421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35831808, while the sum is 58.

The spelling of 16666462626421 in words is "sixteen trillion, six hundred sixty-six billion, four hundred sixty-two million, six hundred twenty-six thousand, four hundred twenty-one".