78055709 has 2 divisors, whose sum is σ = 78055710. Its totient is φ = 78055708.

The previous prime is 78055693. The next prime is 78055711. The reversal of 78055709 is 90755087.

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., 74736025 + 3319684 = 8645^2 + 1822^2 .

It is a cyclic number.

It is not a de Polignac number, because 78055709 - 2⁴ = 78055693 is a prime.

Together with 78055711, 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 (78055739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39027854 + 39027855.

It is an arithmetic number, because the mean of its divisors is an integer number (39027855).

Almost surely, 2^78055709 is an apocalyptic number.

It is an amenable number.

78055709 is a deficient number, since it is larger than the sum of its proper divisors (1).

78055709 is an equidigital number, since it uses as much as digits as its factorization.

78055709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 88200, while the sum is 41.

The square root of 78055709 is about 8834.9142044504. The cubic root of 78055709 is about 427.3675642799.

The spelling of 78055709 in words is "seventy-eight million, fifty-five thousand, seven hundred nine".