316821 has 4 divisors (see below), whose sum is σ = 422432. Its totient is φ = 211212.

The previous prime is 316819. The next prime is 316847. The reversal of 316821 is 128613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 316821 - 2¹ = 316819 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 316821.

It is not an unprimeable number, because it can be changed into a prime (316801) 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, 52801 + ... + 52806.

It is an arithmetic number, because the mean of its divisors is an integer number (105608).

2³¹⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

316821 is a deficient number, since it is larger than the sum of its proper divisors (105611).

316821 is a wasteful number, since it uses less digits than its factorization.

316821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105610.

The product of its digits is 288, while the sum is 21.

The square root of 316821 is about 562.8685459324. The cubic root of 316821 is about 68.1717830888.

The spelling of 316821 in words is "three hundred sixteen thousand, eight hundred twenty-one".