72018161 has 2 divisors, whose sum is σ = 72018162. Its totient is φ = 72018160.

The previous prime is 72018157. The next prime is 72018197. The reversal of 72018161 is 16181027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36675136 + 35343025 = 6056^2 + 5945^2 .

It is a cyclic number.

It is not a de Polignac number, because 72018161 - 2² = 72018157 is a prime.

It is a super-3 number, since 3×72018161³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 72018161.

It is not a weakly prime, because it can be changed into another prime (72011161) 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, 36009080 + 36009081.

It is an arithmetic number, because the mean of its divisors is an integer number (36009081).

Almost surely, 2^72018161 is an apocalyptic number.

It is an amenable number.

72018161 is a deficient number, since it is larger than the sum of its proper divisors (1).

72018161 is an equidigital number, since it uses as much as digits as its factorization.

72018161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 72018161 is about 8486.3514539524. The cubic root of 72018161 is about 416.0517398202.

Adding to 72018161 its reverse (16181027), we get a palindrome (88199188).

It can be divided in two parts, 720 and 18161, that added together give a palindrome (18881).

The spelling of 72018161 in words is "seventy-two million, eighteen thousand, one hundred sixty-one".