20405513 has 2 divisors, whose sum is σ = 20405514. Its totient is φ = 20405512.

The previous prime is 20405501. The next prime is 20405527. The reversal of 20405513 is 31550402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15147664 + 5257849 = 3892^2 + 2293^2 .

It is a cyclic number.

It is not a de Polignac number, because 20405513 - 2¹⁴ = 20389129 is a prime.

It is not a weakly prime, because it can be changed into another prime (20405573) 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 as a sum of consecutive naturals, namely, 10202756 + 10202757.

It is an arithmetic number, because the mean of its divisors is an integer number (10202757).

Almost surely, 2^20405513 is an apocalyptic number.

It is an amenable number.

20405513 is a deficient number, since it is larger than the sum of its proper divisors (1).

20405513 is an equidigital number, since it uses as much as digits as its factorization.

20405513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 20405513 is about 4517.2461743855. The cubic root of 20405513 is about 273.2640532657.

Adding to 20405513 its reverse (31550402), we get a palindrome (51955915).

The spelling of 20405513 in words is "twenty million, four hundred five thousand, five hundred thirteen".