86821 has 8 divisors (see below), whose sum is σ = 101120. Its totient is φ = 73008.

The previous prime is 86813. The next prime is 86837. The reversal of 86821 is 12868.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 86821 - 2³ = 86813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 475 + ... + 631.

It is an arithmetic number, because the mean of its divisors is an integer number (12640).

2⁸⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

86821 is a deficient number, since it is larger than the sum of its proper divisors (14299).

86821 is a wasteful number, since it uses less digits than its factorization.

86821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243.

The product of its digits is 768, while the sum is 25.

The square root of 86821 is about 294.6540344200. The cubic root of 86821 is about 44.2800661743.

The spelling of 86821 in words is "eighty-six thousand, eight hundred twenty-one".