78584221 has 2 divisors, whose sum is σ = 78584222. Its totient is φ = 78584220.

The previous prime is 78584153. The next prime is 78584257. The reversal of 78584221 is 12248587.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56625625 + 21958596 = 7525^2 + 4686^2 .

It is a cyclic number.

It is not a de Polignac number, because 78584221 - 2¹¹ = 78582173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78582221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39292110 + 39292111.

It is an arithmetic number, because the mean of its divisors is an integer number (39292111).

Almost surely, 2^78584221 is an apocalyptic number.

It is an amenable number.

78584221 is a deficient number, since it is larger than the sum of its proper divisors (1).

78584221 is an equidigital number, since it uses as much as digits as its factorization.

78584221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35840, while the sum is 37.

The square root of 78584221 is about 8864.7741652001. The cubic root of 78584221 is about 428.3299581694.

The spelling of 78584221 in words is "seventy-eight million, five hundred eighty-four thousand, two hundred twenty-one".