85659781 has 2 divisors, whose sum is σ = 85659782. Its totient is φ = 85659780.

The previous prime is 85659767. The next prime is 85659839. The reversal of 85659781 is 18795658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51624225 + 34035556 = 7185^2 + 5834^2 .

It is a cyclic number.

It is not a de Polignac number, because 85659781 - 2¹³ = 85651589 is a prime.

It is a super-2 number, since 2×85659781² = 14675196161935922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85659731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42829890 + 42829891.

It is an arithmetic number, because the mean of its divisors is an integer number (42829891).

Almost surely, 2^85659781 is an apocalyptic number.

It is an amenable number.

85659781 is a deficient number, since it is larger than the sum of its proper divisors (1).

85659781 is an equidigital number, since it uses as much as digits as its factorization.

85659781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 49.

The square root of 85659781 is about 9255.2569386268. The cubic root of 85659781 is about 440.8176617424.

The spelling of 85659781 in words is "eighty-five million, six hundred fifty-nine thousand, seven hundred eighty-one".