20513253 has 4 divisors (see below), whose sum is σ = 27351008. Its totient is φ = 13675500.

The previous prime is 20513231. The next prime is 20513257. The reversal of 20513253 is 35231502.

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 not a de Polignac number, because 20513253 - 2⁹ = 20512741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3418873 + ... + 3418878.

It is an arithmetic number, because the mean of its divisors is an integer number (6837752).

Almost surely, 2^20513253 is an apocalyptic number.

It is an amenable number.

20513253 is a deficient number, since it is larger than the sum of its proper divisors (6837755).

20513253 is an equidigital number, since it uses as much as digits as its factorization.

20513253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6837754.

The product of its (nonzero) digits is 900, while the sum is 21.

The square root of 20513253 is about 4529.1558816186. The cubic root of 20513253 is about 273.7441490795.

Adding to 20513253 its reverse (35231502), we get a palindrome (55744755).

The spelling of 20513253 in words is "twenty million, five hundred thirteen thousand, two hundred fifty-three".