19800001 has 4 divisors (see below), whose sum is σ = 21323092. Its totient is φ = 18276912.

The previous prime is 19799993. The next prime is 19800083. The reversal of 19800001 is 10000891.

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 3186225 + 16613776 = 1785^2 + 4076^2 .

It is a cyclic number.

It is not a de Polignac number, because 19800001 - 2³ = 19799993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19800101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 761526 + ... + 761551.

It is an arithmetic number, because the mean of its divisors is an integer number (5330773).

Almost surely, 2^19800001 is an apocalyptic number.

It is an amenable number.

19800001 is a deficient number, since it is larger than the sum of its proper divisors (1523091).

19800001 is a wasteful number, since it uses less digits than its factorization.

19800001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1523090.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 19800001 is about 4449.7192046240. The cubic root of 19800001 is about 270.5339274540.

Adding to 19800001 its reverse (10000891), we get a palindrome (29800892).

The spelling of 19800001 in words is "nineteen million, eight hundred thousand, one".