821630 has 8 divisors (see below), whose sum is σ = 1478952. Its totient is φ = 328648.

The previous prime is 821603. The next prime is 821641. The reversal of 821630 is 36128.

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

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 821630.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 41072 + ... + 41091.

It is an arithmetic number, because the mean of its divisors is an integer number (184869).

2⁸²¹⁶³⁰ is an apocalyptic number.

821630 is a deficient number, since it is larger than the sum of its proper divisors (657322).

821630 is a wasteful number, since it uses less digits than its factorization.

821630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82170.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 821630 is about 906.4380839307. The cubic root of 821630 is about 93.6609940433.

Adding to 821630 its reverse (36128), we get a palindrome (857758).

The spelling of 821630 in words is "eight hundred twenty-one thousand, six hundred thirty".