821902819 has 2 divisors, whose sum is σ = 821902820. Its totient is φ = 821902818.

The previous prime is 821902813. The next prime is 821902877. The reversal of 821902819 is 918209128.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 821902819 - 2¹¹ = 821900771 is a prime.

It is a super-2 number, since 2×821902819² = 1351048487760293522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (821902813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410951409 + 410951410.

It is an arithmetic number, because the mean of its divisors is an integer number (410951410).

Almost surely, 2^821902819 is an apocalyptic number.

821902819 is a deficient number, since it is larger than the sum of its proper divisors (1).

821902819 is an equidigital number, since it uses as much as digits as its factorization.

821902819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 821902819 is about 28668.8475352603. The cubic root of 821902819 is about 936.7135948395.

The spelling of 821902819 in words is "eight hundred twenty-one million, nine hundred two thousand, eight hundred nineteen".