1820513 has 4 divisors (see below), whose sum is σ = 1927620. Its totient is φ = 1713408.

The previous prime is 1820509. The next prime is 1820521. The reversal of 1820513 is 3150281.

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 753424 + 1067089 = 868^2 + 1033^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820513 - 2² = 1820509 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820573) 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, 53528 + ... + 53561.

It is an arithmetic number, because the mean of its divisors is an integer number (481905).

2^1820513 is an apocalyptic number.

It is an amenable number.

1820513 is a deficient number, since it is larger than the sum of its proper divisors (107107).

1820513 is a wasteful number, since it uses less digits than its factorization.

1820513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107106.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 1820513 is about 1349.2638733769. The cubic root of 1820513 is about 122.1043852643.

Adding to 1820513 its reverse (3150281), we get a palindrome (4970794).

The spelling of 1820513 in words is "one million, eight hundred twenty thousand, five hundred thirteen".