78228173 has 2 divisors, whose sum is σ = 78228174. Its totient is φ = 78228172.

The previous prime is 78228151. The next prime is 78228179. The reversal of 78228173 is 37182287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76090729 + 2137444 = 8723^2 + 1462^2 .

It is a cyclic number.

It is not a de Polignac number, because 78228173 - 2⁸ = 78227917 is a prime.

It is a super-2 number, since 2×78228173² = 12239294101835858, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78228179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39114086 + 39114087.

It is an arithmetic number, because the mean of its divisors is an integer number (39114087).

Almost surely, 2^78228173 is an apocalyptic number.

It is an amenable number.

78228173 is a deficient number, since it is larger than the sum of its proper divisors (1).

78228173 is an equidigital number, since it uses as much as digits as its factorization.

78228173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37632, while the sum is 38.

The square root of 78228173 is about 8844.6691854472. The cubic root of 78228173 is about 427.6820887949.

The spelling of 78228173 in words is "seventy-eight million, two hundred twenty-eight thousand, one hundred seventy-three".