72109217 has 2 divisors, whose sum is σ = 72109218. Its totient is φ = 72109216.

The previous prime is 72109187. The next prime is 72109231. The reversal of 72109217 is 71290127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61324561 + 10784656 = 7831^2 + 3284^2 .

It is an emirp because it is prime and its reverse (71290127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72109217 - 2¹⁶ = 72043681 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72109217.

It is not a weakly prime, because it can be changed into another prime (72109267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36054608 + 36054609.

It is an arithmetic number, because the mean of its divisors is an integer number (36054609).

Almost surely, 2^72109217 is an apocalyptic number.

It is an amenable number.

72109217 is a deficient number, since it is larger than the sum of its proper divisors (1).

72109217 is an equidigital number, since it uses as much as digits as its factorization.

72109217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 72109217 is about 8491.7146089585. The cubic root of 72109217 is about 416.2270106672.

The spelling of 72109217 in words is "seventy-two million, one hundred nine thousand, two hundred seventeen".