20431513 has 4 divisors (see below), whose sum is σ = 20450740. Its totient is φ = 20412288.

The previous prime is 20431451. The next prime is 20431547. The reversal of 20431513 is 31513402.

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 2181529 + 18249984 = 1477^2 + 4272^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20431513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20431813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7920 + ... + 10177.

It is an arithmetic number, because the mean of its divisors is an integer number (5112685).

Almost surely, 2^20431513 is an apocalyptic number.

It is an amenable number.

20431513 is a deficient number, since it is larger than the sum of its proper divisors (19227).

20431513 is a wasteful number, since it uses less digits than its factorization.

20431513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19226.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20431513 is about 4520.1231177923. The cubic root of 20431513 is about 273.3800652136.

Adding to 20431513 its reverse (31513402), we get a palindrome (51944915).

The spelling of 20431513 in words is "twenty million, four hundred thirty-one thousand, five hundred thirteen".