1821691841 has 2 divisors, whose sum is σ = 1821691842. Its totient is φ = 1821691840.

The previous prime is 1821691829. The next prime is 1821691867. The reversal of 1821691841 is 1481961281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1483867441 + 337824400 = 38521^2 + 18380^2 .

It is a cyclic number.

It is not a de Polignac number, because 1821691841 - 2⁶ = 1821691777 is a prime.

It is a super-2 number, since 2×1821691841² = 6637122327131938562, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1821691141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910845920 + 910845921.

It is an arithmetic number, because the mean of its divisors is an integer number (910845921).

Almost surely, 2^1821691841 is an apocalyptic number.

It is an amenable number.

1821691841 is a deficient number, since it is larger than the sum of its proper divisors (1).

1821691841 is an equidigital number, since it uses as much as digits as its factorization.

1821691841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 41.

The square root of 1821691841 is about 42681.2820918023. The cubic root of 1821691841 is about 1221.3073508951.

The spelling of 1821691841 in words is "one billion, eight hundred twenty-one million, six hundred ninety-one thousand, eight hundred forty-one".