198909640 has 64 divisors (see below), whose sum is σ = 471951360. Its totient is φ = 75336960.

The previous prime is 198909619. The next prime is 198909643. The reversal of 198909640 is 46909891.

It is not an unprimeable number, because it can be changed into a prime (198909643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56574 + ... + 59986.

It is an arithmetic number, because the mean of its divisors is an integer number (7374240).

Almost surely, 2^198909640 is an apocalyptic number.

198909640 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 198909640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235975680).

198909640 is an abundant number, since it is smaller than the sum of its proper divisors (273041720).

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

198909640 is a wasteful number, since it uses less digits than its factorization.

198909640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502 (or 3498 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 46.

The square root of 198909640 is about 14103.5328907334. The cubic root of 198909640 is about 583.7388664889.

The spelling of 198909640 in words is "one hundred ninety-eight million, nine hundred nine thousand, six hundred forty".