20686647 has 8 divisors (see below), whose sum is σ = 27721600. Its totient is φ = 13721400.

The previous prime is 20686621. The next prime is 20686661. The reversal of 20686647 is 74668602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20686647 - 2⁶ = 20686583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20686607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16729 + ... + 17922.

It is an arithmetic number, because the mean of its divisors is an integer number (3465200).

Almost surely, 2^20686647 is an apocalyptic number.

20686647 is a deficient number, since it is larger than the sum of its proper divisors (7034953).

20686647 is a wasteful number, since it uses less digits than its factorization.

20686647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34853.

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 20686647 is about 4548.2575784579. The cubic root of 20686647 is about 274.5132856433.

The spelling of 20686647 in words is "twenty million, six hundred eighty-six thousand, six hundred forty-seven".