821396 has 24 divisors (see below), whose sum is σ = 1522920. Its totient is φ = 387072.

The previous prime is 821383. The next prime is 821411. The reversal of 821396 is 693128.

It can be written as a sum of positive squares in 4 ways, for example, as 132496 + 688900 = 364^2 + 830^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an Ulam number.

It is a plaindrome in base 15.

It is a congruent number.

It is an unprimeable number.

821396 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 (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8420 + ... + 8516.

It is an arithmetic number, because the mean of its divisors is an integer number (63455).

2⁸²¹³⁹⁶ is an apocalyptic number.

It is an amenable number.

821396 is a deficient number, since it is larger than the sum of its proper divisors (701524).

821396 is a wasteful number, since it uses less digits than its factorization.

821396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 201 counting only the distinct ones).

The product of its digits is 2592, while the sum is 29.

The square root of 821396 is about 906.3089980796. The cubic root of 821396 is about 93.6521016572.

The spelling of 821396 in words is "eight hundred twenty-one thousand, three hundred ninety-six".