161720123 has 2 divisors, whose sum is σ = 161720124. Its totient is φ = 161720122.

The previous prime is 161720101. The next prime is 161720129. The reversal of 161720123 is 321027161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161720123 - 2¹⁸ = 161457979 is a prime.

It is not a weakly prime, because it can be changed into another prime (161720129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80860061 + 80860062.

It is an arithmetic number, because the mean of its divisors is an integer number (80860062).

Almost surely, 2^161720123 is an apocalyptic number.

161720123 is a deficient number, since it is larger than the sum of its proper divisors (1).

161720123 is an equidigital number, since it uses as much as digits as its factorization.

161720123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 161720123 is about 12716.9227016602. The cubic root of 161720123 is about 544.8220646297.

Adding to 161720123 its reverse (321027161), we get a palindrome (482747284).

The spelling of 161720123 in words is "one hundred sixty-one million, seven hundred twenty thousand, one hundred twenty-three".