73821 has 8 divisors (see below), whose sum is σ = 107424. Its totient is φ = 44720.

The previous prime is 73819. The next prime is 73823. The reversal of 73821 is 12837.

It is an interprime number because it is at equal distance from previous prime (73819) and next prime (73823).

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 73821 - 2¹ = 73819 is a prime.

73821 is a lucky number.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1086 + ... + 1151.

It is an arithmetic number, because the mean of its divisors is an integer number (13428).

2⁷³⁸²¹ is an apocalyptic number.

It is an amenable number.

73821 is a deficient number, since it is larger than the sum of its proper divisors (33603).

73821 is a wasteful number, since it uses less digits than its factorization.

73821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2251.

The product of its digits is 336, while the sum is 21.

The square root of 73821 is about 271.7002024291. The cubic root of 73821 is about 41.9494857551.

It can be divided in two parts, 7 and 3821, that added together give a triangular number (3828 = T₈₇).

The spelling of 73821 in words is "seventy-three thousand, eight hundred twenty-one".