20618687 has 2 divisors, whose sum is σ = 20618688. Its totient is φ = 20618686.

The previous prime is 20618683. The next prime is 20618693. The reversal of 20618687 is 78681602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20618687 - 2² = 20618683 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20618687.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20618683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10309343 + 10309344.

It is an arithmetic number, because the mean of its divisors is an integer number (10309344).

Almost surely, 2^20618687 is an apocalyptic number.

20618687 is a deficient number, since it is larger than the sum of its proper divisors (1).

20618687 is an equidigital number, since it uses as much as digits as its factorization.

20618687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 20618687 is about 4540.7804395280. The cubic root of 20618687 is about 274.2123444967.

The spelling of 20618687 in words is "twenty million, six hundred eighteen thousand, six hundred eighty-seven".