1800021959 has 2 divisors, whose sum is σ = 1800021960. Its totient is φ = 1800021958.

The previous prime is 1800021953. The next prime is 1800021961. The reversal of 1800021959 is 9591200081.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1800021959 - 2⁸ = 1800021703 is a prime.

Together with 1800021961, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1800021953) 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, 900010979 + 900010980.

It is an arithmetic number, because the mean of its divisors is an integer number (900010980).

Almost surely, 2^1800021959 is an apocalyptic number.

1800021959 is a deficient number, since it is larger than the sum of its proper divisors (1).

1800021959 is an equidigital number, since it uses as much as digits as its factorization.

1800021959 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 1800021959 is about 42426.6656597004. The cubic root of 1800021959 is about 1216.4453457269.

The spelling of 1800021959 in words is "one billion, eight hundred million, twenty-one thousand, nine hundred fifty-nine".