78578317 has 2 divisors, whose sum is σ = 78578318. Its totient is φ = 78578316.

The previous prime is 78578293. The next prime is 78578321. The reversal of 78578317 is 71387587.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76370121 + 2208196 = 8739^2 + 1486^2 .

It is a cyclic number.

It is not a de Polignac number, because 78578317 - 2¹⁹ = 78054029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78578117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39289158 + 39289159.

It is an arithmetic number, because the mean of its divisors is an integer number (39289159).

Almost surely, 2^78578317 is an apocalyptic number.

It is an amenable number.

78578317 is a deficient number, since it is larger than the sum of its proper divisors (1).

78578317 is an equidigital number, since it uses as much as digits as its factorization.

78578317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 329280, while the sum is 46.

The square root of 78578317 is about 8864.4411555382. The cubic root of 78578317 is about 428.3192311500.

The spelling of 78578317 in words is "seventy-eight million, five hundred seventy-eight thousand, three hundred seventeen".