197851 has 4 divisors (see below), whose sum is σ = 200872. Its totient is φ = 194832.

The previous prime is 197837. The next prime is 197887. The reversal of 197851 is 158791.

197851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 197851 - 2⁹ = 197339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (197831) 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, 1410 + ... + 1543.

It is an arithmetic number, because the mean of its divisors is an integer number (50218).

2¹⁹⁷⁸⁵¹ is an apocalyptic number.

197851 is a deficient number, since it is larger than the sum of its proper divisors (3021).

197851 is an equidigital number, since it uses as much as digits as its factorization.

197851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3020.

The product of its digits is 2520, while the sum is 31.

The square root of 197851 is about 444.8044514166. The cubic root of 197851 is about 58.2701429107.

Subtracting from 197851 its reverse (158791), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 197851 in words is "one hundred ninety-seven thousand, eight hundred fifty-one".