161938321 has 4 divisors (see below), whose sum is σ = 162285552. Its totient is φ = 161591092.

The previous prime is 161938313. The next prime is 161938367. The reversal of 161938321 is 123839161.

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: 123839161 = 3701 ⋅33461.

It is a cyclic number.

It is not a de Polignac number, because 161938321 - 2³ = 161938313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161938391) 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, 172915 + ... + 173848.

It is an arithmetic number, because the mean of its divisors is an integer number (40571388).

Almost surely, 2^161938321 is an apocalyptic number.

It is an amenable number.

161938321 is a deficient number, since it is larger than the sum of its proper divisors (347231).

161938321 is an equidigital number, since it uses as much as digits as its factorization.

161938321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347230.

The product of its digits is 7776, while the sum is 34.

The square root of 161938321 is about 12725.4988507327. The cubic root of 161938321 is about 545.0669850052.

The spelling of 161938321 in words is "one hundred sixty-one million, nine hundred thirty-eight thousand, three hundred twenty-one".