1820398091 has 2 divisors, whose sum is σ = 1820398092. Its totient is φ = 1820398090.

The previous prime is 1820398087. The next prime is 1820398103. The reversal of 1820398091 is 1908930281.

It is a weak prime.

It is an emirp because it is prime and its reverse (1908930281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1820398091 - 2² = 1820398087 is a prime.

It is not a weakly prime, because it can be changed into another prime (1820398291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910199045 + 910199046.

It is an arithmetic number, because the mean of its divisors is an integer number (910199046).

Almost surely, 2^1820398091 is an apocalyptic number.

1820398091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820398091 is an equidigital number, since it uses as much as digits as its factorization.

1820398091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1820398091 is about 42666.1234587817. The cubic root of 1820398091 is about 1221.0181617382.

The spelling of 1820398091 in words is "one billion, eight hundred twenty million, three hundred ninety-eight thousand, ninety-one".