821983 has 4 divisors (see below), whose sum is σ = 839520. Its totient is φ = 804448.

The previous prime is 821971. The next prime is 821993. The reversal of 821983 is 389128.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821983 is a prime.

It is a super-3 number, since 3×821983³ = 1666133366486007261, which contains 333 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821993) 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, 8698 + ... + 8791.

It is an arithmetic number, because the mean of its divisors is an integer number (209880).

2⁸²¹⁹⁸³ is an apocalyptic number.

821983 is a deficient number, since it is larger than the sum of its proper divisors (17537).

821983 is a wasteful number, since it uses less digits than its factorization.

821983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17536.

The product of its digits is 3456, while the sum is 31.

The square root of 821983 is about 906.6327812295. The cubic root of 821983 is about 93.6744054317.

The spelling of 821983 in words is "eight hundred twenty-one thousand, nine hundred eighty-three".