821726 has 8 divisors (see below), whose sum is σ = 1242000. Its totient is φ = 407728.

The previous prime is 821677. The next prime is 821741. The reversal of 821726 is 627128.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 821695 and 821704.

It is a congruent number.

It is an unprimeable number.

821726 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 3 ways as a sum of consecutive naturals, for example, 1226 + ... + 1773.

It is an arithmetic number, because the mean of its divisors is an integer number (155250).

2⁸²¹⁷²⁶ is an apocalyptic number.

821726 is a deficient number, since it is larger than the sum of its proper divisors (420274).

821726 is a wasteful number, since it uses less digits than its factorization.

821726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3138.

The product of its digits is 1344, while the sum is 26.

The square root of 821726 is about 906.4910369110. The cubic root of 821726 is about 93.6646417133.

The spelling of 821726 in words is "eight hundred twenty-one thousand, seven hundred twenty-six".