1821845549 has 2 divisors, whose sum is σ = 1821845550. Its totient is φ = 1821845548.

The previous prime is 1821845521. The next prime is 1821845567. The reversal of 1821845549 is 9455481281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1793946025 + 27899524 = 42355^2 + 5282^2 .

It is an emirp because it is prime and its reverse (9455481281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1821845549 - 2¹² = 1821841453 is a prime.

It is a super-2 number, since 2×1821845549² = 6638242408822222802, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1821815549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910922774 + 910922775.

It is an arithmetic number, because the mean of its divisors is an integer number (910922775).

Almost surely, 2^1821845549 is an apocalyptic number.

It is an amenable number.

1821845549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1821845549 is an equidigital number, since it uses as much as digits as its factorization.

1821845549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 460800, while the sum is 47.

The square root of 1821845549 is about 42683.0827026352. The cubic root of 1821845549 is about 1221.3416998130.

The spelling of 1821845549 in words is "one billion, eight hundred twenty-one million, eight hundred forty-five thousand, five hundred forty-nine".