64821 has 16 divisors (see below), whose sum is σ = 96768. Its totient is φ = 38400.

The previous prime is 64817. The next prime is 64849. The reversal of 64821 is 12846.

It is not a de Polignac number, because 64821 - 2² = 64817 is a prime.

It is a Curzon number.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1561 + ... + 1601.

It is an arithmetic number, because the mean of its divisors is an integer number (6048).

2⁶⁴⁸²¹ is an apocalyptic number.

It is an amenable number.

64821 is a deficient number, since it is larger than the sum of its proper divisors (31947).

64821 is a wasteful number, since it uses less digits than its factorization.

64821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92.

The product of its digits is 384, while the sum is 21.

The square root of 64821 is about 254.5996857814. The cubic root of 64821 is about 40.1703154536.

The spelling of 64821 in words is "sixty-four thousand, eight hundred twenty-one".