169109749681 has 4 divisors (see below), whose sum is σ = 173234377764. Its totient is φ = 164985121600.

The previous prime is 169109749673. The next prime is 169109749777. The reversal of 169109749681 is 186947901961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186947901961 = 43 ⋅4347625627.

It can be written as a sum of positive squares in 2 ways, for example, as 49099469056 + 120010280625 = 221584^2 + 346425^2 .

It is a cyclic number.

It is not a de Polignac number, because 169109749681 - 2³ = 169109749673 is a prime.

It is a super-2 number, since 2×169109749681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (169109749621) 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, 2062313980 + ... + 2062314061.

It is an arithmetic number, because the mean of its divisors is an integer number (43308594441).

Almost surely, 2^169109749681 is an apocalyptic number.

It is an amenable number.

169109749681 is a deficient number, since it is larger than the sum of its proper divisors (4124628083).

169109749681 is an equidigital number, since it uses as much as digits as its factorization.

169109749681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4124628082.

The product of its (nonzero) digits is 5878656, while the sum is 61.

The spelling of 169109749681 in words is "one hundred sixty-nine billion, one hundred nine million, seven hundred forty-nine thousand, six hundred eighty-one".