78047509 has 2 divisors, whose sum is σ = 78047510. Its totient is φ = 78047508.

The previous prime is 78047479. The next prime is 78047513. The reversal of 78047509 is 90574087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75082225 + 2965284 = 8665^2 + 1722^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78047509 is a prime.

It is a super-2 number, since 2×78047509² = 12182827322210162, 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 (78047009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39023754 + 39023755.

It is an arithmetic number, because the mean of its divisors is an integer number (39023755).

Almost surely, 2^78047509 is an apocalyptic number.

It is an amenable number.

78047509 is a deficient number, since it is larger than the sum of its proper divisors (1).

78047509 is an equidigital number, since it uses as much as digits as its factorization.

78047509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70560, while the sum is 40.

The square root of 78047509 is about 8834.4501243711. The cubic root of 78047509 is about 427.3525983161.

The spelling of 78047509 in words is "seventy-eight million, forty-seven thousand, five hundred nine".