198639490900 has 18 divisors (see below), whose sum is σ = 431047695470. Its totient is φ = 79455796320.

The previous prime is 198639490883. The next prime is 198639490901. The reversal of 198639490900 is 9094936891.

It can be written as a sum of positive squares in 3 ways, for example, as 23029883536 + 175609607364 = 151756^2 + 419058^2 .

It is a super-2 number, since 2×198639490900² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198639490901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 993197355 + ... + 993197554.

Almost surely, 2^198639490900 is an apocalyptic number.

198639490900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

198639490900 is an abundant number, since it is smaller than the sum of its proper divisors (232408204570).

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

198639490900 is a wasteful number, since it uses less digits than its factorization.

198639490900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1986394923 (or 1986394916 counting only the distinct ones).

The product of its (nonzero) digits is 3779136, while the sum is 58.

The spelling of 198639490900 in words is "one hundred ninety-eight billion, six hundred thirty-nine million, four hundred ninety thousand, nine hundred".