819969 has 4 divisors (see below), whose sum is σ = 1093296. Its totient is φ = 546644.

The previous prime is 819943. The next prime is 819977. The reversal of 819969 is 969918.

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.

It is a cyclic number.

It is not a de Polignac number, because 819969 - 2⁵ = 819937 is a prime.

It is a super-2 number, since 2×819969² = 1344698321922, which contains 22 as substring.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 819969.

It is not an unprimeable number, because it can be changed into a prime (819989) 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, 136659 + ... + 136664.

It is an arithmetic number, because the mean of its divisors is an integer number (273324).

2⁸¹⁹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

819969 is a deficient number, since it is larger than the sum of its proper divisors (273327).

819969 is a wasteful number, since it uses less digits than its factorization.

819969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273326.

The product of its digits is 34992, while the sum is 42.

The square root of 819969 is about 905.5213967654. The cubic root of 819969 is about 93.5978367167.

The spelling of 819969 in words is "eight hundred nineteen thousand, nine hundred sixty-nine".