813649 has 4 divisors (see below), whose sum is σ = 823536. Its totient is φ = 803764.

The previous prime is 813647. The next prime is 813677. The reversal of 813649 is 946318.

813649 = T₇₃₅ + T₇₃₆ + T₇₃₇.

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: 946318 = 2 ⋅473159.

It is a cyclic number.

It is not a de Polignac number, because 813649 - 2¹ = 813647 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 813649.

It is not an unprimeable number, because it can be changed into a prime (813647) 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, 4819 + ... + 4984.

It is an arithmetic number, because the mean of its divisors is an integer number (205884).

2⁸¹³⁶⁴⁹ is an apocalyptic number.

813649 is the 737-th centered triangular number.

It is an amenable number.

813649 is a deficient number, since it is larger than the sum of its proper divisors (9887).

813649 is an equidigital number, since it uses as much as digits as its factorization.

813649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9886.

The product of its digits is 5184, while the sum is 31.

The square root of 813649 is about 902.0249442227. The cubic root of 813649 is about 93.3567444107.

The spelling of 813649 in words is "eight hundred thirteen thousand, six hundred forty-nine".