197640 has 80 divisors (see below), whose sum is σ = 675180. Its totient is φ = 51840.

The previous prime is 197621. The next prime is 197641. The reversal of 197640 is 46791.

197640 is a `hidden beast` number, since 19 + 7 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 171396 + 26244 = 414^2 + 162^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 9.

It is a zygodrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (197641) by changing a digit.

197640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3210 + ... + 3270.

2¹⁹⁷⁶⁴⁰ is an apocalyptic number.

197640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 197640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (337590).

197640 is an abundant number, since it is smaller than the sum of its proper divisors (477540).

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

197640 is a wasteful number, since it uses less digits than its factorization.

197640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 197640 is about 444.5672052682. The cubic root of 197640 is about 58.2494213012.

It can be divided in two parts, 1976 and 40, that added together give a triangular number (2016 = T₆₃).

The spelling of 197640 in words is "one hundred ninety-seven thousand, six hundred forty".