161829397505 has 8 divisors (see below), whose sum is σ = 194197775400. Its totient is φ = 129461852416.

The previous prime is 161829397451. The next prime is 161829397507. The reversal of 161829397505 is 505793928161.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 23279435776 + 138549961729 = 152576^2 + 372223^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161829397505 - 2¹⁶ = 161829331969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161829397507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 360551 + ... + 673539.

It is an arithmetic number, because the mean of its divisors is an integer number (24274721925).

Almost surely, 2^161829397505 is an apocalyptic number.

It is an amenable number.

161829397505 is a deficient number, since it is larger than the sum of its proper divisors (32368377895).

161829397505 is a wasteful number, since it uses less digits than its factorization.

161829397505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416403.

The product of its (nonzero) digits is 4082400, while the sum is 56.

The spelling of 161829397505 in words is "one hundred sixty-one billion, eight hundred twenty-nine million, three hundred ninety-seven thousand, five hundred five".