86821939 has 4 divisors (see below), whose sum is σ = 86846224. Its totient is φ = 86797656.

The previous prime is 86821921. The next prime is 86821949. The reversal of 86821939 is 93912868.

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

It is a cyclic number.

It is not a de Polignac number, because 86821939 - 2¹⁷ = 86690867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (86821949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5607 + ... + 14320.

It is an arithmetic number, because the mean of its divisors is an integer number (21711556).

Almost surely, 2^86821939 is an apocalyptic number.

86821939 is a deficient number, since it is larger than the sum of its proper divisors (24285).

86821939 is a wasteful number, since it uses less digits than its factorization.

86821939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24284.

The product of its digits is 186624, while the sum is 46.

The square root of 86821939 is about 9317.8290926589. The cubic root of 86821939 is about 442.8022580860.

The spelling of 86821939 in words is "eighty-six million, eight hundred twenty-one thousand, nine hundred thirty-nine".