820513 has 4 divisors (see below), whose sum is σ = 834480. Its totient is φ = 806548.

The previous prime is 820489. The next prime is 820537. The reversal of 820513 is 315028.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (820489) and next prime (820537).

It is a cyclic number.

It is not a de Polignac number, because 820513 - 2⁵ = 820481 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7 and base 16.

It is a zygodrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (820213) 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, 6895 + ... + 7012.

It is an arithmetic number, because the mean of its divisors is an integer number (208620).

2⁸²⁰⁵¹³ is an apocalyptic number.

It is an amenable number.

820513 is a deficient number, since it is larger than the sum of its proper divisors (13967).

820513 is a wasteful number, since it uses less digits than its factorization.

820513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13966.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 820513 is about 905.8217263899. The cubic root of 820513 is about 93.6185309817.

The spelling of 820513 in words is "eight hundred twenty thousand, five hundred thirteen".