85851509 has 2 divisors, whose sum is σ = 85851510. Its totient is φ = 85851508.

The previous prime is 85851487. The next prime is 85851517. The reversal of 85851509 is 90515858.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83210884 + 2640625 = 9122^2 + 1625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85851509 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85851529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42925754 + 42925755.

It is an arithmetic number, because the mean of its divisors is an integer number (42925755).

Almost surely, 2^85851509 is an apocalyptic number.

It is an amenable number.

85851509 is a deficient number, since it is larger than the sum of its proper divisors (1).

85851509 is an equidigital number, since it uses as much as digits as its factorization.

85851509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72000, while the sum is 41.

The square root of 85851509 is about 9265.6089384346. The cubic root of 85851509 is about 441.1463033724.

The spelling of 85851509 in words is "eighty-five million, eight hundred fifty-one thousand, five hundred nine".