72456221 has 2 divisors, whose sum is σ = 72456222. Its totient is φ = 72456220.

The previous prime is 72456191. The next prime is 72456283. The reversal of 72456221 is 12265427.

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., 66748900 + 5707321 = 8170^2 + 2389^2 .

It is a cyclic number.

It is not a de Polignac number, because 72456221 - 2²² = 68261917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72456121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36228110 + 36228111.

It is an arithmetic number, because the mean of its divisors is an integer number (36228111).

Almost surely, 2^72456221 is an apocalyptic number.

It is an amenable number.

72456221 is a deficient number, since it is larger than the sum of its proper divisors (1).

72456221 is an equidigital number, since it uses as much as digits as its factorization.

72456221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 29.

The square root of 72456221 is about 8512.1220033550. The cubic root of 72456221 is about 416.8935984800.

The spelling of 72456221 in words is "seventy-two million, four hundred fifty-six thousand, two hundred twenty-one".