19890000 has 300 divisors, whose sum is σ = 79315236. Its totient is φ = 4608000.

The previous prime is 19889981. The next prime is 19890007. The reversal of 19890000 is 9891.

It can be written as a sum of positive squares in 10 ways, for example, as 16064064 + 3825936 = 4008^2 + 1956^2 .

It is a tau number, because it is divible by the number of its divisors (300).

It is a super-2 number, since 2×19890000² = 791224200000000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19890007) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1169992 + ... + 1170008.

Almost surely, 2^19890000 is an apocalyptic number.

19890000 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 19890000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39657618).

19890000 is an abundant number, since it is smaller than the sum of its proper divisors (59425236).

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

19890000 is a wasteful number, since it uses less digits than its factorization.

19890000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 19890000 is about 4459.8206241956. The cubic root of 19890000 is about 270.9432032859.

Adding to 19890000 its reverse (9891), we get a palindrome (19899891).

The spelling of 19890000 in words is "nineteen million, eight hundred ninety thousand".