1999800001 has 4 divisors (see below), whose sum is σ = 2018146900. Its totient is φ = 1981453104.

The previous prime is 1999799959. The next prime is 1999800031. The reversal of 1999800001 is 1000089991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1696204225 + 303595776 = 41185^2 + 17424^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999800001 - 2¹³ = 1999791809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999800031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9173286 + ... + 9173503.

It is an arithmetic number, because the mean of its divisors is an integer number (504536725).

Almost surely, 2^1999800001 is an apocalyptic number.

It is an amenable number.

1999800001 is a deficient number, since it is larger than the sum of its proper divisors (18346899).

1999800001 is a wasteful number, since it uses less digits than its factorization.

1999800001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18346898.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 1999800001 is about 44719.1234372947. The cubic root of 1999800001 is about 1259.8790513366.

Adding to 1999800001 its reverse (1000089991), we get a palindrome (2999889992).

The spelling of 1999800001 in words is "one billion, nine hundred ninety-nine million, eight hundred thousand, one".