161553923 has 4 divisors (see below), whose sum is σ = 161602320. Its totient is φ = 161505528.

The previous prime is 161553919. The next prime is 161553929. The reversal of 161553923 is 329355161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 329355161 = 17 ⋅19373833.

It is a cyclic number.

It is not a de Polignac number, because 161553923 - 2² = 161553919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161553929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18788 + ... + 26001.

It is an arithmetic number, because the mean of its divisors is an integer number (40400580).

Almost surely, 2^161553923 is an apocalyptic number.

161553923 is a deficient number, since it is larger than the sum of its proper divisors (48397).

161553923 is an equidigital number, since it uses as much as digits as its factorization.

161553923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48396.

The product of its digits is 24300, while the sum is 35.

The square root of 161553923 is about 12710.3864221352. The cubic root of 161553923 is about 544.6353625206.

The spelling of 161553923 in words is "one hundred sixty-one million, five hundred fifty-three thousand, nine hundred twenty-three".