85808581 has 2 divisors, whose sum is σ = 85808582. Its totient is φ = 85808580.

The previous prime is 85808533. The next prime is 85808599. The reversal of 85808581 is 18580858.

85808581 is nontrivially palindromic in base 2 and base 8.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52272900 + 33535681 = 7230^2 + 5791^2 .

It is a cyclic number.

It is not a de Polignac number, because 85808581 - 2¹³ = 85800389 is a prime.

It is a super-2 number, since 2×85808581² = 14726225146467122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85808501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42904290 + 42904291.

It is an arithmetic number, because the mean of its divisors is an integer number (42904291).

Almost surely, 2^85808581 is an apocalyptic number.

It is an amenable number.

85808581 is a deficient number, since it is larger than the sum of its proper divisors (1).

85808581 is an equidigital number, since it uses as much as digits as its factorization.

85808581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 102400, while the sum is 43.

The square root of 85808581 is about 9263.2921253731. The cubic root of 85808581 is about 441.0727628836.

It can be divided in two parts, 8580 and 8581, that added together give a square (17161 = 131²).

The spelling of 85808581 in words is "eighty-five million, eight hundred eight thousand, five hundred eighty-one".