819649 has 4 divisors (see below), whose sum is σ = 825300. Its totient is φ = 814000.

The previous prime is 819647. The next prime is 819653. The reversal of 819649 is 946918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 497025 + 322624 = 705^2 + 568^2 .

It is a cyclic number.

It is not a de Polignac number, because 819649 - 2¹ = 819647 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (819647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2602 + ... + 2899.

It is an arithmetic number, because the mean of its divisors is an integer number (206325).

2⁸¹⁹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

819649 is a deficient number, since it is larger than the sum of its proper divisors (5651).

819649 is a wasteful number, since it uses less digits than its factorization.

819649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5650.

The product of its digits is 15552, while the sum is 37.

The square root of 819649 is about 905.3446857413. The cubic root of 819649 is about 93.5856593438.

It can be divided in two parts, 81 and 9649, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 819649 in words is "eight hundred nineteen thousand, six hundred forty-nine".