161745043765 has 4 divisors (see below), whose sum is σ = 194094052524. Its totient is φ = 129396035008.

The previous prime is 161745043717. The next prime is 161745043771. The reversal of 161745043765 is 567340547161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 567340547161 = 41 ⋅13837574321.

It can be written as a sum of positive squares in 2 ways, for example, as 18129814609 + 143615229156 = 134647^2 + 378966^2 .

It is a cyclic number.

It is not a de Polignac number, because 161745043765 - 2⁷ = 161745043637 is a prime.

It is a super-2 number, since 2×161745043765² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16174504372 + ... + 16174504381.

It is an arithmetic number, because the mean of its divisors is an integer number (48523513131).

Almost surely, 2^161745043765 is an apocalyptic number.

It is an amenable number.

161745043765 is a deficient number, since it is larger than the sum of its proper divisors (32349008759).

161745043765 is an equidigital number, since it uses as much as digits as its factorization.

161745043765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32349008758.

The product of its (nonzero) digits is 2116800, while the sum is 49.

The spelling of 161745043765 in words is "one hundred sixty-one billion, seven hundred forty-five million, forty-three thousand, seven hundred sixty-five".