197840 has 20 divisors (see below), whose sum is σ = 460164. Its totient is φ = 79104.

The previous prime is 197837. The next prime is 197887. The reversal of 197840 is 48791.

It can be written as a sum of positive squares in 2 ways, for example, as 110224 + 87616 = 332^2 + 296^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-4 number, since 4×197840⁴ (a number of 22 digits) contains 4444 as substring.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1157 + ... + 1316.

2¹⁹⁷⁸⁴⁰ is an apocalyptic number.

197840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

197840 is an abundant number, since it is smaller than the sum of its proper divisors (262324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

197840 is a wasteful number, since it uses less digits than its factorization.

197840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2486 (or 2480 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 197840 is about 444.7920862605. The cubic root of 197840 is about 58.2690630013.

The spelling of 197840 in words is "one hundred ninety-seven thousand, eight hundred forty".