198721000 has 64 divisors (see below), whose sum is σ = 489528000. Its totient is φ = 75297600.

The previous prime is 198720953. The next prime is 198721013. The reversal of 198721000 is 127891.

It is a self number, because there is not a number n which added to its sum of digits gives 198721000.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13771 + ... + 24229.

It is an arithmetic number, because the mean of its divisors is an integer number (7648875).

Almost surely, 2^198721000 is an apocalyptic number.

198721000 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 198721000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244764000).

198721000 is an abundant number, since it is smaller than the sum of its proper divisors (290807000).

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

198721000 is a wasteful number, since it uses less digits than its factorization.

198721000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10499 (or 10485 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 198721000 is about 14096.8436183424. The cubic root of 198721000 is about 583.5542745832.

Adding to 198721000 its reverse (127891), we get a palindrome (198848891).

The spelling of 198721000 in words is "one hundred ninety-eight million, seven hundred twenty-one thousand".