19999900 has 18 divisors (see below), whose sum is σ = 43400000. Its totient is φ = 7999920.

The previous prime is 19999897. The next prime is 19999909. The reversal of 19999900 is 999991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999909) 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 in 5 ways as a sum of consecutive naturals, for example, 99900 + ... + 100099.

Almost surely, 2^19999900 is an apocalyptic number.

19999900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19999900 is an abundant number, since it is smaller than the sum of its proper divisors (23400100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19999900 is a wasteful number, since it uses less digits than its factorization.

19999900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200013 (or 200006 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 46.

The square root of 19999900 is about 4472.1247746457. The cubic root of 19999900 is about 271.4413092558.

The spelling of 19999900 in words is "nineteen million, nine hundred ninety-nine thousand, nine hundred".