78954209 has 2 divisors, whose sum is σ = 78954210. Its totient is φ = 78954208.

The previous prime is 78954173. The next prime is 78954223. The reversal of 78954209 is 90245987.

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., 65286400 + 13667809 = 8080^2 + 3697^2 .

It is a cyclic number.

It is not a de Polignac number, because 78954209 - 2¹⁶ = 78888673 is a prime.

It is a super-3 number, since 3×78954209³ (a number of 25 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 78954209.

It is not a weakly prime, because it can be changed into another prime (78954299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39477104 + 39477105.

It is an arithmetic number, because the mean of its divisors is an integer number (39477105).

Almost surely, 2^78954209 is an apocalyptic number.

It is an amenable number.

78954209 is a deficient number, since it is larger than the sum of its proper divisors (1).

78954209 is an equidigital number, since it uses as much as digits as its factorization.

78954209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 78954209 is about 8885.6180989282. The cubic root of 78954209 is about 429.0011229352.

The spelling of 78954209 in words is "seventy-eight million, nine hundred fifty-four thousand, two hundred nine".