85281781 has 8 divisors (see below), whose sum is σ = 94324664. Its totient is φ = 76593600.

The previous prime is 85281751. The next prime is 85281787. The reversal of 85281781 is 18718258.

It can be written as a sum of positive squares in 4 ways, for example, as 8439025 + 76842756 = 2905^2 + 8766^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 85281781 - 2¹⁹ = 84757493 is a prime.

It is a super-2 number, since 2×85281781² = 14545964341063922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85281787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88170 + ... + 89131.

It is an arithmetic number, because the mean of its divisors is an integer number (11790583).

Almost surely, 2^85281781 is an apocalyptic number.

It is an amenable number.

85281781 is a deficient number, since it is larger than the sum of its proper divisors (9042883).

85281781 is a wasteful number, since it uses less digits than its factorization.

85281781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177351.

The product of its digits is 35840, while the sum is 40.

The square root of 85281781 is about 9234.8135335804. The cubic root of 85281781 is about 440.1682913399.

The spelling of 85281781 in words is "eighty-five million, two hundred eighty-one thousand, seven hundred eighty-one".