20686663 has 4 divisors (see below), whose sum is σ = 21245800. Its totient is φ = 20127528.

The previous prime is 20686661. The next prime is 20686681. The reversal of 20686663 is 36668602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20686663 - 2¹ = 20686661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 559099 = 20686663 / (2 + 0 + 6 + 8 + 6 + 6 + 6 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20686661) 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, 279513 + ... + 279586.

It is an arithmetic number, because the mean of its divisors is an integer number (5311450).

Almost surely, 2^20686663 is an apocalyptic number.

20686663 is a deficient number, since it is larger than the sum of its proper divisors (559137).

20686663 is an equidigital number, since it uses as much as digits as its factorization.

20686663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559136.

The product of its (nonzero) digits is 62208, while the sum is 37.

The square root of 20686663 is about 4548.2593373729. The cubic root of 20686663 is about 274.5133564170.

The spelling of 20686663 in words is "twenty million, six hundred eighty-six thousand, six hundred sixty-three".