20618137 has 4 divisors (see below), whose sum is σ = 20630016. Its totient is φ = 20606260.

The previous prime is 20618123. The next prime is 20618141. The reversal of 20618137 is 73181602.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20618137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20618107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2773 + ... + 6994.

It is an arithmetic number, because the mean of its divisors is an integer number (5157504).

Almost surely, 2^20618137 is an apocalyptic number.

It is an amenable number.

20618137 is a deficient number, since it is larger than the sum of its proper divisors (11879).

20618137 is an equidigital number, since it uses as much as digits as its factorization.

20618137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11878.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 20618137 is about 4540.7198768477. The cubic root of 20618137 is about 274.2099062856.

Adding to 20618137 its reverse (73181602), we get a palindrome (93799739).

The spelling of 20618137 in words is "twenty million, six hundred eighteen thousand, one hundred thirty-seven".