821713 has 4 divisors (see below), whose sum is σ = 824320. Its totient is φ = 819108.

The previous prime is 821677. The next prime is 821741. The reversal of 821713 is 317128.

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 a de Polignac number, because none of the positive numbers 2^k-821713 is a prime.

It is a Duffinian number.

821713 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (821753) 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, 753 + ... + 1486.

It is an arithmetic number, because the mean of its divisors is an integer number (206080).

2⁸²¹⁷¹³ is an apocalyptic number.

It is an amenable number.

821713 is a deficient number, since it is larger than the sum of its proper divisors (2607).

821713 is a wasteful number, since it uses less digits than its factorization.

821713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2606.

The product of its digits is 336, while the sum is 22.

The square root of 821713 is about 906.4838663760. The cubic root of 821713 is about 93.6641477746.

The spelling of 821713 in words is "eight hundred twenty-one thousand, seven hundred thirteen".