161216123 has 4 divisors (see below), whose sum is σ = 162695280. Its totient is φ = 159736968.

The previous prime is 161216119. The next prime is 161216149. The reversal of 161216123 is 321612161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161216123 - 2² = 161216119 is a prime.

It is a super-2 number, since 2×161216123² = 51981276630302258, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161216173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 739415 + ... + 739632.

It is an arithmetic number, because the mean of its divisors is an integer number (40673820).

Almost surely, 2^161216123 is an apocalyptic number.

161216123 is a deficient number, since it is larger than the sum of its proper divisors (1479157).

161216123 is a wasteful number, since it uses less digits than its factorization.

161216123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1479156.

The product of its digits is 432, while the sum is 23.

The square root of 161216123 is about 12697.0911235605. The cubic root of 161216123 is about 544.2554971889.

Adding to 161216123 its reverse (321612161), we get a palindrome (482828284).

The spelling of 161216123 in words is "one hundred sixty-one million, two hundred sixteen thousand, one hundred twenty-three".