198918551 has 8 divisors (see below), whose sum is σ = 214512144. Its totient is φ = 183366720.

The previous prime is 198918527. The next prime is 198918553. The reversal of 198918551 is 155819891.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198918551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 198918496 and 198918505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198918553) 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, 161 + ... + 19946.

It is an arithmetic number, because the mean of its divisors is an integer number (26814018).

Almost surely, 2^198918551 is an apocalyptic number.

198918551 is a deficient number, since it is larger than the sum of its proper divisors (15593593).

198918551 is a wasteful number, since it uses less digits than its factorization.

198918551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20881.

The product of its digits is 129600, while the sum is 47.

The square root of 198918551 is about 14103.8488009479. The cubic root of 198918551 is about 583.7475833772.

The spelling of 198918551 in words is "one hundred ninety-eight million, nine hundred eighteen thousand, five hundred fifty-one".