1997971 has 4 divisors (see below), whose sum is σ = 2046744. Its totient is φ = 1949200.

The previous prime is 1997969. The next prime is 1997999. The reversal of 1997971 is 1797991.

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 1997971 - 2¹ = 1997969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1997911) 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, 24325 + ... + 24406.

It is an arithmetic number, because the mean of its divisors is an integer number (511686).

2^1997971 is an apocalyptic number.

1997971 is a deficient number, since it is larger than the sum of its proper divisors (48773).

1997971 is an equidigital number, since it uses as much as digits as its factorization.

1997971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48772.

The product of its digits is 35721, while the sum is 43.

The square root of 1997971 is about 1413.4960205108. The cubic root of 1997971 is about 125.9494842432.

The spelling of 1997971 in words is "one million, nine hundred ninety-seven thousand, nine hundred seventy-one".