198642581 has 8 divisors (see below), whose sum is σ = 205359000. Its totient is φ = 192015360.

The previous prime is 198642551. The next prime is 198642583. The reversal of 198642581 is 185246891.

It can be written as a sum of positive squares in 4 ways, for example, as 32103556 + 166539025 = 5666^2 + 12905^2 .

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 198642581 - 2¹⁸ = 198380437 is a prime.

It is a super-2 number, since 2×198642581² = 78917749972683122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198642583) 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, 17756 + ... + 26693.

It is an arithmetic number, because the mean of its divisors is an integer number (25669875).

Almost surely, 2^198642581 is an apocalyptic number.

It is an amenable number.

198642581 is a deficient number, since it is larger than the sum of its proper divisors (6716419).

198642581 is a wasteful number, since it uses less digits than its factorization.

198642581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44599.

The product of its digits is 138240, while the sum is 44.

The square root of 198642581 is about 14094.0619056396. The cubic root of 198642581 is about 583.4775040297.

The spelling of 198642581 in words is "one hundred ninety-eight million, six hundred forty-two thousand, five hundred eighty-one".