78253709 has 2 divisors, whose sum is σ = 78253710. Its totient is φ = 78253708.

The previous prime is 78253699. The next prime is 78253711. The reversal of 78253709 is 90735287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40921609 + 37332100 = 6397^2 + 6110^2 .

It is a cyclic number.

It is not a de Polignac number, because 78253709 - 2⁸ = 78253453 is a prime.

It is a super-2 number, since 2×78253709² = 12247285944513362, which contains 22 as substring.

Together with 78253711, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78253729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39126854 + 39126855.

It is an arithmetic number, because the mean of its divisors is an integer number (39126855).

Almost surely, 2^78253709 is an apocalyptic number.

It is an amenable number.

78253709 is a deficient number, since it is larger than the sum of its proper divisors (1).

78253709 is an equidigital number, since it uses as much as digits as its factorization.

78253709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 78253709 is about 8846.1126490680. The cubic root of 78253709 is about 427.7286197793.

The spelling of 78253709 in words is "seventy-eight million, two hundred fifty-three thousand, seven hundred nine".