86921 has 4 divisors (see below), whose sum is σ = 92052. Its totient is φ = 81792.

The previous prime is 86869. The next prime is 86923. The reversal of 86921 is 12968.

86921 = T₃₁ + T₃₂ + ... + T₈₁.

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

It can be written as a sum of positive squares in 2 ways, for example, as 26896 + 60025 = 164^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 86921 - 2⁶ = 86857 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 86921.

It is not an unprimeable number, because it can be changed into a prime (86923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2540 + ... + 2573.

It is an arithmetic number, because the mean of its divisors is an integer number (23013).

2⁸⁶⁹²¹ is an apocalyptic number.

It is an amenable number.

86921 is a deficient number, since it is larger than the sum of its proper divisors (5131).

86921 is a wasteful number, since it uses less digits than its factorization.

86921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5130.

The product of its digits is 864, while the sum is 26.

The square root of 86921 is about 294.8236761185. The cubic root of 86921 is about 44.2970601721.

The spelling of 86921 in words is "eighty-six thousand, nine hundred twenty-one".