1971871 has 4 divisors (see below), whose sum is σ = 2151144. Its totient is φ = 1792600.

The previous prime is 1971869. The next prime is 1971887. The reversal of 1971871 is 1781791.

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 1971871 - 2¹ = 1971869 is a prime.

It is a Duffinian number.

1971871 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1951871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89620 + ... + 89641.

It is an arithmetic number, because the mean of its divisors is an integer number (537786).

2^1971871 is an apocalyptic number.

1971871 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1971871 is a deficient number, since it is larger than the sum of its proper divisors (179273).

1971871 is a wasteful number, since it uses less digits than its factorization.

1971871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179272.

The product of its digits is 3528, while the sum is 34.

The square root of 1971871 is about 1404.2332427343. The cubic root of 1971871 is about 125.3986419917.

The spelling of 1971871 in words is "one million, nine hundred seventy-one thousand, eight hundred seventy-one".