165872381 has 2 divisors, whose sum is σ = 165872382. Its totient is φ = 165872380.

The previous prime is 165872327. The next prime is 165872459. The reversal of 165872381 is 183278561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125664100 + 40208281 = 11210^2 + 6341^2 .

It is a cyclic number.

It is not a de Polignac number, because 165872381 - 2¹⁰ = 165871357 is a prime.

It is a super-2 number, since 2×165872381² = 55027293557218322, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165872081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82936190 + 82936191.

It is an arithmetic number, because the mean of its divisors is an integer number (82936191).

Almost surely, 2^165872381 is an apocalyptic number.

It is an amenable number.

165872381 is a deficient number, since it is larger than the sum of its proper divisors (1).

165872381 is an equidigital number, since it uses as much as digits as its factorization.

165872381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 41.

The square root of 165872381 is about 12879.1451967900. The cubic root of 165872381 is about 549.4455911971.

The spelling of 165872381 in words is "one hundred sixty-five million, eight hundred seventy-two thousand, three hundred eighty-one".