821399 has 8 divisors (see below), whose sum is σ = 870912. Its totient is φ = 773080.

The previous prime is 821383. The next prime is 821411. The reversal of 821399 is 993128.

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

It is a cyclic number.

It is not a de Polignac number, because 821399 - 2⁴ = 821383 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1382 + ... + 1884.

It is an arithmetic number, because the mean of its divisors is an integer number (108864).

2⁸²¹³⁹⁹ is an apocalyptic number.

821399 is a deficient number, since it is larger than the sum of its proper divisors (49513).

821399 is a wasteful number, since it uses less digits than its factorization.

821399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597.

The product of its digits is 3888, while the sum is 32.

The square root of 821399 is about 906.3106531427. The cubic root of 821399 is about 93.6522156728.

The spelling of 821399 in words is "eight hundred twenty-one thousand, three hundred ninety-nine".