198021915 has 128 divisors (see below), whose sum is σ = 440832000. Its totient is φ = 83140992.

The previous prime is 198021883. The next prime is 198021919. The reversal of 198021915 is 519120891.

It is not a de Polignac number, because 198021915 - 2⁵ = 198021883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 198021915.

It is not an unprimeable number, because it can be changed into a prime (198021919) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 994986 + ... + 995184.

It is an arithmetic number, because the mean of its divisors is an integer number (3444000).

Almost surely, 2^198021915 is an apocalyptic number.

198021915 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

198021915 is an abundant number, since it is smaller than the sum of its proper divisors (242810085).

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

198021915 is an equidigital number, since it uses as much as digits as its factorization.

198021915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 36.

The square root of 198021915 is about 14072.0259735406. The cubic root of 198021915 is about 582.8691710784.

The spelling of 198021915 in words is "one hundred ninety-eight million, twenty-one thousand, nine hundred fifteen".