20813513 has 4 divisors (see below), whose sum is σ = 23786880. Its totient is φ = 17840148.

The previous prime is 20813509. The next prime is 20813563. The reversal of 20813513 is 31531802.

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 20813513 - 2² = 20813509 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20813563) 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, 1486673 + ... + 1486686.

It is an arithmetic number, because the mean of its divisors is an integer number (5946720).

Almost surely, 2^20813513 is an apocalyptic number.

It is an amenable number.

20813513 is a deficient number, since it is larger than the sum of its proper divisors (2973367).

20813513 is an equidigital number, since it uses as much as digits as its factorization.

20813513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2973366.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 20813513 is about 4562.1829204888. The cubic root of 20813513 is about 275.0733159891.

The spelling of 20813513 in words is "twenty million, eight hundred thirteen thousand, five hundred thirteen".