811232216021 has 2 divisors, whose sum is σ = 811232216022. Its totient is φ = 811232216020.

The previous prime is 811232216017. The next prime is 811232216089. The reversal of 811232216021 is 120612232118.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 733739575396 + 77492640625 = 856586^2 + 278375^2 .

It is a cyclic number.

It is not a de Polignac number, because 811232216021 - 2² = 811232216017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (811232210021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405616108010 + 405616108011.

It is an arithmetic number, because the mean of its divisors is an integer number (405616108011).

Almost surely, 2^811232216021 is an apocalyptic number.

It is an amenable number.

811232216021 is a deficient number, since it is larger than the sum of its proper divisors (1).

811232216021 is an equidigital number, since it uses as much as digits as its factorization.

811232216021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 29.

Adding to 811232216021 its reverse (120612232118), we get a palindrome (931844448139).

The spelling of 811232216021 in words is "eight hundred eleven billion, two hundred thirty-two million, two hundred sixteen thousand, twenty-one".