198779490 has 144 divisors (see below), whose sum is σ = 639931968. Its totient is φ = 41917824.

The previous prime is 198779489. The next prime is 198779491. The reversal of 198779490 is 94977891.

198779490 is a `hidden beast` number, since 1 + 9 + 87 + 79 + 490 = 666.

It is an interprime number because it is at equal distance from previous prime (198779489) and next prime (198779491).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198779491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 105537 + ... + 107403.

It is an arithmetic number, because the mean of its divisors is an integer number (4443972).

Almost surely, 2^198779490 is an apocalyptic number.

198779490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 198779490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (319965984).

198779490 is an abundant number, since it is smaller than the sum of its proper divisors (441152478).

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

198779490 is a wasteful number, since it uses less digits than its factorization.

198779490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1913 (or 1897 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 54.

The square root of 198779490 is about 14098.9180435947. The cubic root of 198779490 is about 583.6115219154.

The spelling of 198779490 in words is "one hundred ninety-eight million, seven hundred seventy-nine thousand, four hundred ninety".