161223643 has 4 divisors (see below), whose sum is σ = 184255600. Its totient is φ = 138191688.

The previous prime is 161223619. The next prime is 161223661. The reversal of 161223643 is 346322161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346322161 = 13687 ⋅25303.

It is a cyclic number.

It is not a de Polignac number, because 161223643 - 2⁵ = 161223611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161223443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11515968 + ... + 11515981.

It is an arithmetic number, because the mean of its divisors is an integer number (46063900).

Almost surely, 2^161223643 is an apocalyptic number.

161223643 is a deficient number, since it is larger than the sum of its proper divisors (23031957).

161223643 is an equidigital number, since it uses as much as digits as its factorization.

161223643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23031956.

The product of its digits is 5184, while the sum is 28.

The square root of 161223643 is about 12697.3872509269. The cubic root of 161223643 is about 544.2639594064.

The spelling of 161223643 in words is "one hundred sixty-one million, two hundred twenty-three thousand, six hundred forty-three".