1821998539 has 2 divisors, whose sum is σ = 1821998540. Its totient is φ = 1821998538.

The previous prime is 1821998533. The next prime is 1821998593. The reversal of 1821998539 is 9358991281.

Together with next prime (1821998593) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1821998539 - 2¹³ = 1821990347 is a prime.

It is a super-2 number, since 2×1821998539² = 6639357352236269042, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1821998539.

It is not a weakly prime, because it can be changed into another prime (1821998533) 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, 910999269 + 910999270.

It is an arithmetic number, because the mean of its divisors is an integer number (910999270).

Almost surely, 2^1821998539 is an apocalyptic number.

1821998539 is a deficient number, since it is larger than the sum of its proper divisors (1).

1821998539 is an equidigital number, since it uses as much as digits as its factorization.

1821998539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1399680, while the sum is 55.

The square root of 1821998539 is about 42684.8748270391. The cubic root of 1821998539 is about 1221.3758863620.

The spelling of 1821998539 in words is "one billion, eight hundred twenty-one million, nine hundred ninety-eight thousand, five hundred thirty-nine".