1997789 has 4 divisors (see below), whose sum is σ = 2115324. Its totient is φ = 1880256.

The previous prime is 1997773. The next prime is 1997813. The reversal of 1997789 is 9877991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9877991 = 1319 ⋅7489.

It can be written as a sum of positive squares in 2 ways, for example, as 912025 + 1085764 = 955^2 + 1042^2 .

It is a cyclic number.

It is not a de Polignac number, because 1997789 - 2⁴ = 1997773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1997719) 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, 58742 + ... + 58775.

It is an arithmetic number, because the mean of its divisors is an integer number (528831).

2^1997789 is an apocalyptic number.

It is an amenable number.

1997789 is a deficient number, since it is larger than the sum of its proper divisors (117535).

1997789 is a wasteful number, since it uses less digits than its factorization.

1997789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117534.

The product of its digits is 285768, while the sum is 50.

The square root of 1997789 is about 1413.4316396628. The cubic root of 1997789 is about 125.9456597795.

The spelling of 1997789 in words is "one million, nine hundred ninety-seven thousand, seven hundred eighty-nine".