85297781 has 2 divisors, whose sum is σ = 85297782. Its totient is φ = 85297780.

The previous prime is 85297763. The next prime is 85297811. The reversal of 85297781 is 18779258.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44222500 + 41075281 = 6650^2 + 6409^2 .

It is a cyclic number.

It is not a de Polignac number, because 85297781 - 2⁶ = 85297717 is a prime.

It is a super-2 number, since 2×85297781² = 14551422887047922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85297181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42648890 + 42648891.

It is an arithmetic number, because the mean of its divisors is an integer number (42648891).

Almost surely, 2^85297781 is an apocalyptic number.

It is an amenable number.

85297781 is a deficient number, since it is larger than the sum of its proper divisors (1).

85297781 is an equidigital number, since it uses as much as digits as its factorization.

85297781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282240, while the sum is 47.

The square root of 85297781 is about 9235.6797800703. The cubic root of 85297781 is about 440.1958167668.

The spelling of 85297781 in words is "eighty-five million, two hundred ninety-seven thousand, seven hundred eighty-one".