78395221 has 2 divisors, whose sum is σ = 78395222. Its totient is φ = 78395220.

The previous prime is 78395209. The next prime is 78395231. The reversal of 78395221 is 12259387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52272900 + 26122321 = 7230^2 + 5111^2 .

It is a cyclic number.

It is not a de Polignac number, because 78395221 - 2⁹ = 78394709 is a prime.

It is a super-2 number, since 2×78395221² = 12291621351277682, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78395231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39197610 + 39197611.

It is an arithmetic number, because the mean of its divisors is an integer number (39197611).

Almost surely, 2^78395221 is an apocalyptic number.

It is an amenable number.

78395221 is a deficient number, since it is larger than the sum of its proper divisors (1).

78395221 is an equidigital number, since it uses as much as digits as its factorization.

78395221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 37.

The square root of 78395221 is about 8854.1075778420. The cubic root of 78395221 is about 427.9862956715.

The spelling of 78395221 in words is "seventy-eight million, three hundred ninety-five thousand, two hundred twenty-one".