821919559849 has 2 divisors, whose sum is σ = 821919559850. Its totient is φ = 821919559848.

The previous prime is 821919559829. The next prime is 821919559907. The reversal of 821919559849 is 948955919128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 675613309849 + 146306250000 = 821957^2 + 382500^2 .

It is a cyclic number.

It is not a de Polignac number, because 821919559849 - 2⁹ = 821919559337 is a prime.

It is not a weakly prime, because it can be changed into another prime (821919559829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410959779924 + 410959779925.

It is an arithmetic number, because the mean of its divisors is an integer number (410959779925).

Almost surely, 2^821919559849 is an apocalyptic number.

It is an amenable number.

821919559849 is a deficient number, since it is larger than the sum of its proper divisors (1).

821919559849 is an equidigital number, since it uses as much as digits as its factorization.

821919559849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 83980800, while the sum is 70.

The spelling of 821919559849 in words is "eight hundred twenty-one billion, nine hundred nineteen million, five hundred fifty-nine thousand, eight hundred forty-nine".