19800999 has 18 divisors (see below), whose sum is σ = 29906240. Its totient is φ = 12623688.

The previous prime is 19800961. The next prime is 19801003. The reversal of 19800999 is 99900891.

It is not a de Polignac number, because 19800999 - 2⁷ = 19800871 is a prime.

It is a super-2 number, since 2×19800999² = 784159122796002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19800929) 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 17 ways as a sum of consecutive naturals, for example, 2682 + ... + 6840.

Almost surely, 2^19800999 is an apocalyptic number.

19800999 is a deficient number, since it is larger than the sum of its proper divisors (10105241).

19800999 is a wasteful number, since it uses less digits than its factorization.

19800999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4211 (or 4185 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The square root of 19800999 is about 4449.8313451186. The cubic root of 19800999 is about 270.5384727117.

The spelling of 19800999 in words is "nineteen million, eight hundred thousand, nine hundred ninety-nine".