821381 has 8 divisors (see below), whose sum is σ = 907200. Its totient is φ = 737440.

The previous prime is 821377. The next prime is 821383. The reversal of 821381 is 183128.

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

It is not a de Polignac number, because 821381 - 2² = 821377 is a prime.

It is a super-2 number, since 2×821381² = 1349333494322, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a nialpdrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 821381.

It is not an unprimeable number, because it can be changed into a prime (821383) by changing a digit.

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, 560 + ... + 1398.

It is an arithmetic number, because the mean of its divisors is an integer number (113400).

2⁸²¹³⁸¹ is an apocalyptic number.

It is an amenable number.

821381 is a deficient number, since it is larger than the sum of its proper divisors (85819).

821381 is a wasteful number, since it uses less digits than its factorization.

821381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 939.

The product of its digits is 384, while the sum is 23.

The square root of 821381 is about 906.3007227185. The cubic root of 821381 is about 93.6515315748.

The spelling of 821381 in words is "eight hundred twenty-one thousand, three hundred eighty-one".