821213 has 4 divisors (see below), whose sum is σ = 823200. Its totient is φ = 819228.

The previous prime is 821209. The next prime is 821263. The reversal of 821213 is 312128.

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 a cyclic number.

It is not a de Polignac number, because 821213 - 2² = 821209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 821191 and 821200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821263) 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, 113 + ... + 1286.

It is an arithmetic number, because the mean of its divisors is an integer number (205800).

2⁸²¹²¹³ is an apocalyptic number.

It is an amenable number.

821213 is a deficient number, since it is larger than the sum of its proper divisors (1987).

821213 is a wasteful number, since it uses less digits than its factorization.

821213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1986.

The product of its digits is 96, while the sum is 17.

The square root of 821213 is about 906.2080335111. The cubic root of 821213 is about 93.6451461783.

The spelling of 821213 in words is "eight hundred twenty-one thousand, two hundred thirteen".