197981 has 4 divisors (see below), whose sum is σ = 226272. Its totient is φ = 169692.

The previous prime is 197971. The next prime is 198013. The reversal of 197981 is 189791.

197981 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-197981 is a prime.

It is a super-2 number, since 2×197981² = 78392952722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 197981.

It is not an unprimeable number, because it can be changed into a prime (197921) 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, 14135 + ... + 14148.

It is an arithmetic number, because the mean of its divisors is an integer number (56568).

2¹⁹⁷⁹⁸¹ is an apocalyptic number.

It is an amenable number.

197981 is a deficient number, since it is larger than the sum of its proper divisors (28291).

197981 is an equidigital number, since it uses as much as digits as its factorization.

197981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28290.

The product of its digits is 4536, while the sum is 35.

The square root of 197981 is about 444.9505590512. The cubic root of 197981 is about 58.2829024453.

It can be divided in two parts, 19 and 7981, that added together give a cube (8000 = 20³).

The spelling of 197981 in words is "one hundred ninety-seven thousand, nine hundred eighty-one".