19990000 has 50 divisors (see below), whose sum is σ = 48422000. Its totient is φ = 7992000.

The previous prime is 19989997. The next prime is 19990031. The reversal of 19990000 is 9991.

It is a tau number, because it is divible by the number of its divisors (50).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9001 + ... + 10999.

It is an arithmetic number, because the mean of its divisors is an integer number (968440).

Almost surely, 2^19990000 is an apocalyptic number.

19990000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19990000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24211000).

19990000 is an abundant number, since it is smaller than the sum of its proper divisors (28432000).

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

19990000 is an equidigital number, since it uses as much as digits as its factorization.

19990000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2027 (or 2006 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 28.

The square root of 19990000 is about 4471.0177812216. The cubic root of 19990000 is about 271.3965138237.

Adding to 19990000 its reverse (9991), we get a palindrome (19999991).

The spelling of 19990000 in words is "nineteen million, nine hundred ninety thousand".