85978729 has 2 divisors, whose sum is σ = 85978730. Its totient is φ = 85978728.

The previous prime is 85978723. The next prime is 85978733. The reversal of 85978729 is 92787958.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75429225 + 10549504 = 8685^2 + 3248^2 .

It is a cyclic number.

It is not a de Polignac number, because 85978729 - 2³ = 85978721 is a prime.

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 85978729.

It is not a weakly prime, because it can be changed into another prime (85978721) 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, 42989364 + 42989365.

It is an arithmetic number, because the mean of its divisors is an integer number (42989365).

Almost surely, 2^85978729 is an apocalyptic number.

It is an amenable number.

85978729 is a deficient number, since it is larger than the sum of its proper divisors (1).

85978729 is an equidigital number, since it uses as much as digits as its factorization.

85978729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 55.

The square root of 85978729 is about 9272.4715691125. The cubic root of 85978729 is about 441.3641016545.

The spelling of 85978729 in words is "eighty-five million, nine hundred seventy-eight thousand, seven hundred twenty-nine".