197491871 has 4 divisors (see below), whose sum is σ = 207886200. Its totient is φ = 187097544.

The previous prime is 197491867. The next prime is 197491883. The reversal of 197491871 is 178194791.

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 197491871 - 2² = 197491867 is a prime.

It is a super-2 number, since 2×197491871² = 78006078222161282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (197491471) 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, 5197136 + ... + 5197173.

It is an arithmetic number, because the mean of its divisors is an integer number (51971550).

Almost surely, 2^197491871 is an apocalyptic number.

197491871 is a deficient number, since it is larger than the sum of its proper divisors (10394329).

197491871 is a wasteful number, since it uses less digits than its factorization.

197491871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10394328.

The product of its digits is 127008, while the sum is 47.

The square root of 197491871 is about 14053.1801027383. The cubic root of 197491871 is about 582.3486523114.

The spelling of 197491871 in words is "one hundred ninety-seven million, four hundred ninety-one thousand, eight hundred seventy-one".