85840781 has 4 divisors (see below), whose sum is σ = 92443932. Its totient is φ = 79237632.

The previous prime is 85840751. The next prime is 85840787. The reversal of 85840781 is 18704858.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18704858 = 2 ⋅9352429.

It can be written as a sum of positive squares in 2 ways, for example, as 27394756 + 58446025 = 5234^2 + 7645^2 .

It is a cyclic number.

It is not a de Polignac number, because 85840781 - 2⁶ = 85840717 is a prime.

It is a super-2 number, since 2×85840781² = 14737279365379922, 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 (85840787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3301556 + ... + 3301581.

It is an arithmetic number, because the mean of its divisors is an integer number (23110983).

Almost surely, 2^85840781 is an apocalyptic number.

It is an amenable number.

85840781 is a deficient number, since it is larger than the sum of its proper divisors (6603151).

85840781 is a wasteful number, since it uses less digits than its factorization.

85840781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6603150.

The product of its (nonzero) digits is 71680, while the sum is 41.

The square root of 85840781 is about 9265.0300053481. The cubic root of 85840781 is about 441.1279274007.

The spelling of 85840781 in words is "eighty-five million, eight hundred forty thousand, seven hundred eighty-one".