1997819 has 4 divisors (see below), whose sum is σ = 2009160. Its totient is φ = 1986480.

The previous prime is 1997813. The next prime is 1997833. The reversal of 1997819 is 9187991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9187991 = 631 ⋅14561.

It is a cyclic number.

It is not a de Polignac number, because 1997819 - 2¹⁶ = 1932283 is a prime.

It is a super-2 number, since 2×1997819² = 7982561513522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1997819.

It is not an unprimeable number, because it can be changed into a prime (1997813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5402 + ... + 5759.

It is an arithmetic number, because the mean of its divisors is an integer number (502290).

2^1997819 is an apocalyptic number.

1997819 is a deficient number, since it is larger than the sum of its proper divisors (11341).

1997819 is a wasteful number, since it uses less digits than its factorization.

1997819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11340.

The product of its digits is 40824, while the sum is 44.

The square root of 1997819 is about 1413.4422520924. The cubic root of 1997819 is about 125.9462902016.

The spelling of 1997819 in words is "one million, nine hundred ninety-seven thousand, eight hundred nineteen".