1989997 has 4 divisors (see below), whose sum is σ = 2036320. Its totient is φ = 1943676.

The previous prime is 1989989. The next prime is 1990007. The reversal of 1989997 is 7999891.

1989997 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7999891 = 31 ⋅258061.

It is a cyclic number.

It is not a de Polignac number, because 1989997 - 2³ = 1989989 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989947) 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, 23097 + ... + 23182.

It is an arithmetic number, because the mean of its divisors is an integer number (509080).

2^1989997 is an apocalyptic number.

It is an amenable number.

1989997 is a deficient number, since it is larger than the sum of its proper divisors (46323).

1989997 is an equidigital number, since it uses as much as digits as its factorization.

1989997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46322.

The product of its digits is 367416, while the sum is 52.

The square root of 1989997 is about 1410.6725346444. The cubic root of 1989997 is about 125.7817039874.

The spelling of 1989997 in words is "one million, nine hundred eighty-nine thousand, nine hundred ninety-seven".