165972281 has 2 divisors, whose sum is σ = 165972282. Its totient is φ = 165972280.

The previous prime is 165972259. The next prime is 165972293. The reversal of 165972281 is 182279561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116748025 + 49224256 = 10805^2 + 7016^2 .

It is a cyclic number.

It is not a de Polignac number, because 165972281 - 2¹⁸ = 165710137 is a prime.

It is a super-2 number, since 2×165972281² = 55093596120685922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165972211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82986140 + 82986141.

It is an arithmetic number, because the mean of its divisors is an integer number (82986141).

Almost surely, 2^165972281 is an apocalyptic number.

It is an amenable number.

165972281 is a deficient number, since it is larger than the sum of its proper divisors (1).

165972281 is an equidigital number, since it uses as much as digits as its factorization.

165972281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 41.

The square root of 165972281 is about 12883.0229759944. The cubic root of 165972281 is about 549.5558739708. Note that the first 3 decimals are identical.

The spelling of 165972281 in words is "one hundred sixty-five million, nine hundred seventy-two thousand, two hundred eighty-one".