161405523 has 6 divisors (see below), whose sum is σ = 233141324. Its totient is φ = 107603676.

The previous prime is 161405521. The next prime is 161405527. The reversal of 161405523 is 325504161.

It is not a de Polignac number, because 161405523 - 2¹ = 161405521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161405521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8966965 + ... + 8966982.

Almost surely, 2^161405523 is an apocalyptic number.

161405523 is a deficient number, since it is larger than the sum of its proper divisors (71735801).

161405523 is a wasteful number, since it uses less digits than its factorization.

161405523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17933953 (or 17933950 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 161405523 is about 12704.5473355016. The cubic root of 161405523 is about 544.4685479433.

Adding to 161405523 its reverse (325504161), we get a palindrome (486909684).

The spelling of 161405523 in words is "one hundred sixty-one million, four hundred five thousand, five hundred twenty-three".