78522221 has 2 divisors, whose sum is σ = 78522222. Its totient is φ = 78522220.

The previous prime is 78522211. The next prime is 78522239. The reversal of 78522221 is 12222587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78517321 + 4900 = 8861^2 + 70^2 .

It is a cyclic number.

It is not a de Polignac number, because 78522221 - 2¹⁴ = 78505837 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78522211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39261110 + 39261111.

It is an arithmetic number, because the mean of its divisors is an integer number (39261111).

Almost surely, 2^78522221 is an apocalyptic number.

It is an amenable number.

78522221 is a deficient number, since it is larger than the sum of its proper divisors (1).

78522221 is an equidigital number, since it uses as much as digits as its factorization.

78522221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4480, while the sum is 29.

The square root of 78522221 is about 8861.2764881816. The cubic root of 78522221 is about 428.2172831135.

The spelling of 78522221 in words is "seventy-eight million, five hundred twenty-two thousand, two hundred twenty-one".