198619861 has 4 divisors (see below), whose sum is σ = 216676224. Its totient is φ = 180563500.

The previous prime is 198619859. The next prime is 198619879. The reversal of 198619861 is 168916891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 198619861 - 2¹ = 198619859 is a prime.

198619861 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198619261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9028165 + ... + 9028186.

It is an arithmetic number, because the mean of its divisors is an integer number (54169056).

Almost surely, 2^198619861 is an apocalyptic number.

198619861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

198619861 is a deficient number, since it is larger than the sum of its proper divisors (18056363).

198619861 is a wasteful number, since it uses less digits than its factorization.

198619861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18056362.

The product of its digits is 186624, while the sum is 49.

The square root of 198619861 is about 14093.2558693866. The cubic root of 198619861 is about 583.4552578522.

The spelling of 198619861 in words is "one hundred ninety-eight million, six hundred nineteen thousand, eight hundred sixty-one".