822147721 has 2 divisors, whose sum is σ = 822147722. Its totient is φ = 822147720.

The previous prime is 822147701. The next prime is 822147749. The reversal of 822147721 is 127741228.

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., 748788496 + 73359225 = 27364^2 + 8565^2 .

It is a cyclic number.

It is not a de Polignac number, because 822147721 - 2¹¹ = 822145673 is a prime.

It is not a weakly prime, because it can be changed into another prime (822147701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411073860 + 411073861.

It is an arithmetic number, because the mean of its divisors is an integer number (411073861).

Almost surely, 2^822147721 is an apocalyptic number.

It is an amenable number.

822147721 is a deficient number, since it is larger than the sum of its proper divisors (1).

822147721 is an equidigital number, since it uses as much as digits as its factorization.

822147721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12544, while the sum is 34.

The square root of 822147721 is about 28673.1184387049. The cubic root of 822147721 is about 936.8066229714.

Adding to 822147721 its reverse (127741228), we get a palindrome (949888949).

The spelling of 822147721 in words is "eight hundred twenty-two million, one hundred forty-seven thousand, seven hundred twenty-one".