1997771 has 2 divisors, whose sum is σ = 1997772. Its totient is φ = 1997770.

The previous prime is 1997753. The next prime is 1997773. The reversal of 1997771 is 1777991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1997771 - 2⁶ = 1997707 is a prime.

It is a Sophie Germain prime.

Together with 1997773, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1997773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998885 + 998886.

It is an arithmetic number, because the mean of its divisors is an integer number (998886).

2^1997771 is an apocalyptic number.

1997771 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997771 is an equidigital number, since it uses as much as digits as its factorization.

1997771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27783, while the sum is 41.

The square root of 1997771 is about 1413.4252721669. The cubic root of 1997771 is about 125.9452815233.

The spelling of 1997771 in words is "one million, nine hundred ninety-seven thousand, seven hundred seventy-one".