83856991 has 4 divisors (see below), whose sum is σ = 83894184. Its totient is φ = 83819800.

The previous prime is 83856979. The next prime is 83857003. The reversal of 83856991 is 19965838.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (83856979) and next prime (83857003).

It is a cyclic number.

It is not a de Polignac number, because 83856991 - 2¹¹ = 83854943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83856901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14980 + ... + 19801.

It is an arithmetic number, because the mean of its divisors is an integer number (20973546).

Almost surely, 2^83856991 is an apocalyptic number.

83856991 is a deficient number, since it is larger than the sum of its proper divisors (37193).

83856991 is a wasteful number, since it uses less digits than its factorization.

83856991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37192.

The product of its digits is 466560, while the sum is 49.

The square root of 83856991 is about 9157.3462859062. The cubic root of 83856991 is about 437.7032368388.

It can be divided in two parts, 8385 and 6991, that added together give a square (15376 = 124²).

The spelling of 83856991 in words is "eighty-three million, eight hundred fifty-six thousand, nine hundred ninety-one".