72217231 has 2 divisors, whose sum is σ = 72217232. Its totient is φ = 72217230.

The previous prime is 72217183. The next prime is 72217267. The reversal of 72217231 is 13271227.

It is a strong prime.

It is an emirp because it is prime and its reverse (13271227) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72217231 - 2¹¹ = 72215183 is a prime.

It is a super-2 number, since 2×72217231² = 10430656906614722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 72217196 and 72217205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72217531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36108615 + 36108616.

It is an arithmetic number, because the mean of its divisors is an integer number (36108616).

Almost surely, 2^72217231 is an apocalyptic number.

72217231 is a deficient number, since it is larger than the sum of its proper divisors (1).

72217231 is an equidigital number, since it uses as much as digits as its factorization.

72217231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1176, while the sum is 25.

The square root of 72217231 is about 8498.0721931506. The cubic root of 72217231 is about 416.4347322171.

Adding to 72217231 its reverse (13271227), we get a palindrome (85488458).

The spelling of 72217231 in words is "seventy-two million, two hundred seventeen thousand, two hundred thirty-one".