20518037 has 4 divisors (see below), whose sum is σ = 20799180. Its totient is φ = 20236896.

The previous prime is 20518033. The next prime is 20518061. The reversal of 20518037 is 73081502.

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 17648401 + 2869636 = 4201^2 + 1694^2 .

It is a cyclic number.

It is not a de Polignac number, because 20518037 - 2² = 20518033 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20517997 and 20518015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20518033) 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, 140462 + ... + 140607.

It is an arithmetic number, because the mean of its divisors is an integer number (5199795).

Almost surely, 2^20518037 is an apocalyptic number.

It is an amenable number.

20518037 is a deficient number, since it is larger than the sum of its proper divisors (281143).

20518037 is an equidigital number, since it uses as much as digits as its factorization.

20518037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281142.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 20518037 is about 4529.6839845623. The cubic root of 20518037 is about 273.7654278469.

Adding to 20518037 its reverse (73081502), we get a palindrome (93599539).

The spelling of 20518037 in words is "twenty million, five hundred eighteen thousand, thirty-seven".