821966 has 4 divisors (see below), whose sum is σ = 1232952. Its totient is φ = 410982.

The previous prime is 821941. The next prime is 821971. The reversal of 821966 is 669128.

821966 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205490 + ... + 205493.

It is an arithmetic number, because the mean of its divisors is an integer number (308238).

2⁸²¹⁹⁶⁶ is an apocalyptic number.

821966 is a deficient number, since it is larger than the sum of its proper divisors (410986).

821966 is a wasteful number, since it uses less digits than its factorization.

821966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410985.

The product of its digits is 5184, while the sum is 32.

The square root of 821966 is about 906.6234058307. The cubic root of 821966 is about 93.6737596455.

It can be divided in two parts, 82 and 1966, that added together give a 11-th power (2048 = 2¹¹).

The spelling of 821966 in words is "eight hundred twenty-one thousand, nine hundred sixty-six".