821947 has 8 divisors (see below), whose sum is σ = 972000. Its totient is φ = 680064.

The previous prime is 821941. The next prime is 821971. The reversal of 821947 is 749128.

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

It is not a de Polignac number, because 821947 - 2³ = 821939 is a prime.

It is a Duffinian number.

821947 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (821941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1822 + ... + 2227.

It is an arithmetic number, because the mean of its divisors is an integer number (121500).

2⁸²¹⁹⁴⁷ is an apocalyptic number.

821947 is a deficient number, since it is larger than the sum of its proper divisors (150053).

821947 is a wasteful number, since it uses less digits than its factorization.

821947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4085.

The product of its digits is 4032, while the sum is 31.

The square root of 821947 is about 906.6129273290. The cubic root of 821947 is about 93.6730378739.

The spelling of 821947 in words is "eight hundred twenty-one thousand, nine hundred forty-seven".