1819563821 has 2 divisors, whose sum is σ = 1819563822. Its totient is φ = 1819563820.

The previous prime is 1819563799. The next prime is 1819563841. The reversal of 1819563821 is 1283659181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1758879721 + 60684100 = 41939^2 + 7790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1819563821 is a prime.

It is a super-3 number, since 3×1819563821³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1819563841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909781910 + 909781911.

It is an arithmetic number, because the mean of its divisors is an integer number (909781911).

Almost surely, 2^1819563821 is an apocalyptic number.

It is an amenable number.

1819563821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1819563821 is an equidigital number, since it uses as much as digits as its factorization.

1819563821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 44.

The square root of 1819563821 is about 42656.3456123471. The cubic root of 1819563821 is about 1220.8316064860.

The spelling of 1819563821 in words is "one billion, eight hundred nineteen million, five hundred sixty-three thousand, eight hundred twenty-one".