78959009 has 2 divisors, whose sum is σ = 78959010. Its totient is φ = 78959008.

The previous prime is 78958973. The next prime is 78959011. The reversal of 78959009 is 90095987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72199009 + 6760000 = 8497^2 + 2600^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78959009 is a prime.

Together with 78959011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78959039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39479504 + 39479505.

It is an arithmetic number, because the mean of its divisors is an integer number (39479505).

Almost surely, 2^78959009 is an apocalyptic number.

It is an amenable number.

78959009 is a deficient number, since it is larger than the sum of its proper divisors (1).

78959009 is an equidigital number, since it uses as much as digits as its factorization.

78959009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 47.

The square root of 78959009 is about 8885.8881942100. Note that the first 3 decimals coincide. The cubic root of 78959009 is about 429.0098164286.

The spelling of 78959009 in words is "seventy-eight million, nine hundred fifty-nine thousand, nine".