161405123 has 16 divisors (see below), whose sum is σ = 187453440. Its totient is φ = 137347200.

The previous prime is 161405093. The next prime is 161405143. The reversal of 161405123 is 321504161.

It is a cyclic number.

It is not a de Polignac number, because 161405123 - 2¹⁰ = 161404099 is a prime.

It is a super-2 number, since 2×161405123² = 52103227461290258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161405143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33458 + ... + 37976.

It is an arithmetic number, because the mean of its divisors is an integer number (11715840).

Almost surely, 2^161405123 is an apocalyptic number.

161405123 is a deficient number, since it is larger than the sum of its proper divisors (26048317).

161405123 is a wasteful number, since it uses less digits than its factorization.

161405123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4738.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 161405123 is about 12704.5315930970. The cubic root of 161405123 is about 544.4680981702.

Adding to 161405123 its reverse (321504161), we get a palindrome (482909284).

The spelling of 161405123 in words is "one hundred sixty-one million, four hundred five thousand, one hundred twenty-three".