198621857 has 8 divisors (see below), whose sum is σ = 228390336. Its totient is φ = 169201872.

The previous prime is 198621847. The next prime is 198621869. The reversal of 198621857 is 758126891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 198621857 - 2¹² = 198617761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198621827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85898 + ... + 88179.

It is an arithmetic number, because the mean of its divisors is an integer number (28548792).

Almost surely, 2^198621857 is an apocalyptic number.

It is an amenable number.

198621857 is a deficient number, since it is larger than the sum of its proper divisors (29768479).

198621857 is a wasteful number, since it uses less digits than its factorization.

198621857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174247.

The product of its digits is 241920, while the sum is 47.

The square root of 198621857 is about 14093.3266832214. The cubic root of 198621857 is about 583.4572122939.

The spelling of 198621857 in words is "one hundred ninety-eight million, six hundred twenty-one thousand, eight hundred fifty-seven".