85951991 has 16 divisors (see below), whose sum is σ = 92316000. Its totient is φ = 79792128.

The previous prime is 85951979. The next prime is 85951993. The reversal of 85951991 is 19915958.

It is a cyclic number.

It is not a de Polignac number, because 85951991 - 2¹⁸ = 85689847 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85951993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 274451 + ... + 274763.

It is an arithmetic number, because the mean of its divisors is an integer number (5769750).

Almost surely, 2^85951991 is an apocalyptic number.

85951991 is a deficient number, since it is larger than the sum of its proper divisors (6364009).

85951991 is a wasteful number, since it uses less digits than its factorization.

85951991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578.

The product of its digits is 145800, while the sum is 47.

The square root of 85951991 is about 9271.0296623406. The cubic root of 85951991 is about 441.3183445352.

The spelling of 85951991 in words is "eighty-five million, nine hundred fifty-one thousand, nine hundred ninety-one".