161242705 has 32 divisors (see below), whose sum is σ = 221798304. Its totient is φ = 111476736.

The previous prime is 161242681. The next prime is 161242723. The reversal of 161242705 is 507242161.

161242705 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 16 ways, for example, as 91470096 + 69772609 = 9564^2 + 8353^2 .

It is a 4-Lehmer number, since φ(161242705) divides (161242705-1)⁴.

It is a cyclic number.

It is a Carmichael number.

It is a de Polignac number, because none of the positive numbers 2^k-161242705 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 372169 + ... + 372601.

It is an arithmetic number, because the mean of its divisors is an integer number (6931197).

It is a Poulet number, since it divides 2^161242704-1.

Almost surely, 2^161242705 is an apocalyptic number.

It is an amenable number.

161242705 is a deficient number, since it is larger than the sum of its proper divisors (60555599).

161242705 is a wasteful number, since it uses less digits than its factorization.

161242705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 805.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 161242705 is about 12698.1378556070. The cubic root of 161242705 is about 544.2854085987.

Adding to 161242705 its reverse (507242161), we get a palindrome (668484866).

The spelling of 161242705 in words is "one hundred sixty-one million, two hundred forty-two thousand, seven hundred five".