78314221 has 2 divisors, whose sum is σ = 78314222. Its totient is φ = 78314220.

The previous prime is 78314147. The next prime is 78314227. The reversal of 78314221 is 12241387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54597321 + 23716900 = 7389^2 + 4870^2 .

It is an emirp because it is prime and its reverse (12241387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78314221 - 2¹⁵ = 78281453 is a prime.

It is a super-2 number, since 2×78314221² = 12266234421673682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78314221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78314227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39157110 + 39157111.

It is an arithmetic number, because the mean of its divisors is an integer number (39157111).

Almost surely, 2^78314221 is an apocalyptic number.

It is an amenable number.

78314221 is a deficient number, since it is larger than the sum of its proper divisors (1).

78314221 is an equidigital number, since it uses as much as digits as its factorization.

78314221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 28.

The square root of 78314221 is about 8849.5322475259. The cubic root of 78314221 is about 427.8388426510.

The spelling of 78314221 in words is "seventy-eight million, three hundred fourteen thousand, two hundred twenty-one".