198421640172 has 72 divisors (see below), whose sum is σ = 598414486320. Its totient is φ = 56691895680.

The previous prime is 198421640129. The next prime is 198421640191. The reversal of 198421640172 is 271046124891.

198421640172 is a `hidden beast` number, since 19 + 8 + 421 + 6 + 40 + 172 = 666.

It is a super-2 number, since 2×198421640172² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18742029 + ... + 18752612.

It is an arithmetic number, because the mean of its divisors is an integer number (8311312310).

Almost surely, 2^198421640172 is an apocalyptic number.

198421640172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

198421640172 is an abundant number, since it is smaller than the sum of its proper divisors (399992846148).

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

198421640172 is a wasteful number, since it uses less digits than its factorization.

198421640172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37494668 (or 37494653 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 198421640172 in words is "one hundred ninety-eight billion, four hundred twenty-one million, six hundred forty thousand, one hundred seventy-two".