821020220771 has 8 divisors (see below), whose sum is σ = 822144056160. Its totient is φ = 819896732928.

The previous prime is 821020220723. The next prime is 821020220821. The reversal of 821020220771 is 177022020128.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821020220771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821020225771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4830485 + ... + 4997561.

It is an arithmetic number, because the mean of its divisors is an integer number (102768007020).

Almost surely, 2^821020220771 is an apocalyptic number.

821020220771 is a deficient number, since it is larger than the sum of its proper divisors (1123835389).

821020220771 is a wasteful number, since it uses less digits than its factorization.

821020220771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173773.

The product of its (nonzero) digits is 6272, while the sum is 32.

Adding to 821020220771 its reverse (177022020128), we get a palindrome (998042240899).

The spelling of 821020220771 in words is "eight hundred twenty-one billion, twenty million, two hundred twenty thousand, seven hundred seventy-one".