16661172205477 has 2 divisors, whose sum is σ = 16661172205478. Its totient is φ = 16661172205476.

The previous prime is 16661172205459. The next prime is 16661172205501. The reversal of 16661172205477 is 77450227116661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15247353705796 + 1413818499681 = 3904786^2 + 1189041^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16661172205477 is a prime.

It is a super-3 number, since 3×16661172205477³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16661172205417) 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, 8330586102738 + 8330586102739.

It is an arithmetic number, because the mean of its divisors is an integer number (8330586102739).

Almost surely, 2^{16661172205477} is an apocalyptic number.

It is an amenable number.

16661172205477 is a deficient number, since it is larger than the sum of its proper divisors (1).

16661172205477 is an equidigital number, since it uses as much as digits as its factorization.

16661172205477 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5927040, while the sum is 55.

The spelling of 16661172205477 in words is "sixteen trillion, six hundred sixty-one billion, one hundred seventy-two million, two hundred five thousand, four hundred seventy-seven".