20513243 has 6 divisors (see below), whose sum is σ = 21027492. Its totient is φ = 20011280.

The previous prime is 20513231. The next prime is 20513257. The reversal of 20513243 is 34231502.

It is a happy number.

It is not a de Polignac number, because 20513243 - 2¹² = 20509147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20513443) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4421 + ... + 7782.

It is an arithmetic number, because the mean of its divisors is an integer number (3504582).

Almost surely, 2^20513243 is an apocalyptic number.

20513243 is a deficient number, since it is larger than the sum of its proper divisors (514249).

20513243 is an equidigital number, since it uses as much as digits as its factorization.

20513243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12285 (or 12244 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 20513243 is about 4529.1547776600. The cubic root of 20513243 is about 273.7441045970.

Adding to 20513243 its reverse (34231502), we get a palindrome (54744745).

The spelling of 20513243 in words is "twenty million, five hundred thirteen thousand, two hundred forty-three".