161236321 has 4 divisors (see below), whose sum is σ = 163969200. Its totient is φ = 158503444.

The previous prime is 161236319. The next prime is 161236333. The reversal of 161236321 is 123632161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 123632161 = 11119².

It is a cyclic number.

It is not a de Polignac number, because 161236321 - 2¹ = 161236319 is a prime.

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 (161236021) 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, 1366351 + ... + 1366468.

It is an arithmetic number, because the mean of its divisors is an integer number (40992300).

Almost surely, 2^161236321 is an apocalyptic number.

It is an amenable number.

161236321 is a deficient number, since it is larger than the sum of its proper divisors (2732879).

161236321 is an equidigital number, since it uses as much as digits as its factorization.

161236321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2732878.

The product of its digits is 1296, while the sum is 25.

The square root of 161236321 is about 12697.8864776781. The cubic root of 161236321 is about 544.2782252992.

Adding to 161236321 its reverse (123632161), we get a palindrome (284868482).

The spelling of 161236321 in words is "one hundred sixty-one million, two hundred thirty-six thousand, three hundred twenty-one".