198651981 has 8 divisors (see below), whose sum is σ = 288948384. Its totient is φ = 120395120.

The previous prime is 198651961. The next prime is 198651983. The reversal of 198651981 is 189156891.

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

It is a cyclic number.

It is not a de Polignac number, because 198651981 - 2⁶ = 198651917 is a prime.

It is a super-2 number, since 2×198651981² = 78925219110448722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 198651981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198651983) 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, 3009846 + ... + 3009911.

It is an arithmetic number, because the mean of its divisors is an integer number (36118548).

Almost surely, 2^198651981 is an apocalyptic number.

198651981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

198651981 is a deficient number, since it is larger than the sum of its proper divisors (90296403).

198651981 is a wasteful number, since it uses less digits than its factorization.

198651981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6019771.

The product of its digits is 155520, while the sum is 48.

The square root of 198651981 is about 14094.3953754675. The cubic root of 198651981 is about 583.4867074979.

The spelling of 198651981 in words is "one hundred ninety-eight million, six hundred fifty-one thousand, nine hundred eighty-one".