78492509 has 2 divisors, whose sum is σ = 78492510. Its totient is φ = 78492508.

The previous prime is 78492493. The next prime is 78492529. The reversal of 78492509 is 90529487.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57304900 + 21187609 = 7570^2 + 4603^2 .

It is a cyclic number.

It is not a de Polignac number, because 78492509 - 2⁴ = 78492493 is a prime.

It is a super-2 number, since 2×78492509² = 12322147938230162, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78492509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78492529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39246254 + 39246255.

It is an arithmetic number, because the mean of its divisors is an integer number (39246255).

Almost surely, 2^78492509 is an apocalyptic number.

It is an amenable number.

78492509 is a deficient number, since it is larger than the sum of its proper divisors (1).

78492509 is an equidigital number, since it uses as much as digits as its factorization.

78492509 is an evil number, because the sum of its binary digits is even.

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

The square root of 78492509 is about 8859.5998216624. The cubic root of 78492509 is about 428.1632652959.

The spelling of 78492509 in words is "seventy-eight million, four hundred ninety-two thousand, five hundred nine".