16661172206761 has 4 divisors (see below), whose sum is σ = 16661429083332. Its totient is φ = 16660915330192.

The previous prime is 16661172206699. The next prime is 16661172206773. The reversal of 16661172206761 is 16760227116661.

16661172206761 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14498084293225 + 2163087913536 = 3807635^2 + 1470744^2 .

It is a cyclic number.

It is not a de Polignac number, because 16661172206761 - 2²⁷ = 16661037989033 is a prime.

It is a super-2 number, since 2×16661172206761² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16661172206699 and 16661172206708.

It is not an unprimeable number, because it can be changed into a prime (16661172209761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128340970 + ... + 128470723.

It is an arithmetic number, because the mean of its divisors is an integer number (4165357270833).

Almost surely, 2^{16661172206761} is an apocalyptic number.

It is an amenable number.

16661172206761 is a deficient number, since it is larger than the sum of its proper divisors (256876571).

16661172206761 is an equidigital number, since it uses as much as digits as its factorization.

16661172206761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256876570.

The product of its (nonzero) digits is 1524096, while the sum is 52.

The spelling of 16661172206761 in words is "sixteen trillion, six hundred sixty-one billion, one hundred seventy-two million, two hundred six thousand, seven hundred sixty-one".