198641657 has 4 divisors (see below), whose sum is σ = 199831296. Its totient is φ = 197452020.

The previous prime is 198641647. The next prime is 198641689. The reversal of 198641657 is 756146891.

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 198641657 - 2¹⁶ = 198576121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198641627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 594569 + ... + 594902.

It is an arithmetic number, because the mean of its divisors is an integer number (49957824).

Almost surely, 2^198641657 is an apocalyptic number.

It is an amenable number.

198641657 is a deficient number, since it is larger than the sum of its proper divisors (1189639).

198641657 is a wasteful number, since it uses less digits than its factorization.

198641657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189638.

The product of its digits is 362880, while the sum is 47.

The square root of 198641657 is about 14094.0291258391. The cubic root of 198641657 is about 583.4765993327.

The spelling of 198641657 in words is "one hundred ninety-eight million, six hundred forty-one thousand, six hundred fifty-seven".