72181229 has 2 divisors, whose sum is σ = 72181230. Its totient is φ = 72181228.

The previous prime is 72181223. The next prime is 72181253. The reversal of 72181229 is 92218127.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68923204 + 3258025 = 8302^2 + 1805^2 .

It is a cyclic number.

It is not a de Polignac number, because 72181229 - 2⁸ = 72180973 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_4238753 and since 72181229 and 4238753 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 72181195 and 72181204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72181223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36090614 + 36090615.

It is an arithmetic number, because the mean of its divisors is an integer number (36090615).

Almost surely, 2^72181229 is an apocalyptic number.

It is an amenable number.

72181229 is a deficient number, since it is larger than the sum of its proper divisors (1).

72181229 is an equidigital number, since it uses as much as digits as its factorization.

72181229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 72181229 is about 8495.9536839604. The cubic root of 72181229 is about 416.3655198557.

The spelling of 72181229 in words is "seventy-two million, one hundred eighty-one thousand, two hundred twenty-nine".