85978709 has 2 divisors, whose sum is σ = 85978710. Its totient is φ = 85978708.

The previous prime is 85978703. The next prime is 85978721. The reversal of 85978709 is 90787958.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77827684 + 8151025 = 8822^2 + 2855^2 .

It is a cyclic number.

It is not a de Polignac number, because 85978709 - 2¹⁶ = 85913173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85978703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42989354 + 42989355.

It is an arithmetic number, because the mean of its divisors is an integer number (42989355).

Almost surely, 2^85978709 is an apocalyptic number.

It is an amenable number.

85978709 is a deficient number, since it is larger than the sum of its proper divisors (1).

85978709 is an equidigital number, since it uses as much as digits as its factorization.

85978709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1270080, while the sum is 53.

The square root of 85978709 is about 9272.4704906513. The cubic root of 85978709 is about 441.3640674318.

Subtracting 85978709 from its reverse (90787958), we obtain a square (4809249 = 2193²).

The spelling of 85978709 in words is "eighty-five million, nine hundred seventy-eight thousand, seven hundred nine".