161323381 has 4 divisors (see below), whose sum is σ = 161442252. Its totient is φ = 161204512.

The previous prime is 161323373. The next prime is 161323427. The reversal of 161323381 is 183323161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 116834481 + 44488900 = 10809^2 + 6670^2 .

It is a cyclic number.

It is not a de Polignac number, because 161323381 - 2³ = 161323373 is a prime.

It is a super-2 number, since 2×161323381² = 52050466514542322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161323181) 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, 57376 + ... + 60121.

It is an arithmetic number, because the mean of its divisors is an integer number (40360563).

Almost surely, 2^161323381 is an apocalyptic number.

It is an amenable number.

161323381 is a deficient number, since it is larger than the sum of its proper divisors (118871).

161323381 is a wasteful number, since it uses less digits than its factorization.

161323381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118870.

The product of its digits is 2592, while the sum is 28.

The square root of 161323381 is about 12701.3141446072. The cubic root of 161323381 is about 544.3761691869.

The spelling of 161323381 in words is "one hundred sixty-one million, three hundred twenty-three thousand, three hundred eighty-one".