198978978 has 32 divisors (see below), whose sum is σ = 434863872. Its totient is φ = 60195600.

The previous prime is 198978973. The next prime is 198979009. The reversal of 198978978 is 879879891.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is not an unprimeable number, because it can be changed into a prime (198978973) 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, 43425 + ... + 47787.

It is an arithmetic number, because the mean of its divisors is an integer number (13589496).

Almost surely, 2^198978978 is an apocalyptic number.

198978978 is an abundant number, since it is smaller than the sum of its proper divisors (235884894).

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

198978978 is a wasteful number, since it uses less digits than its factorization.

198978978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5070.

The product of its digits is 18289152, while the sum is 66.

The square root of 198978978 is about 14105.9908549524. The cubic root of 198978978 is about 583.8066872061.

The spelling of 198978978 in words is "one hundred ninety-eight million, nine hundred seventy-eight thousand, nine hundred seventy-eight".