20668551 has 8 divisors (see below), whose sum is σ = 28230384. Its totient is φ = 13442880.

The previous prime is 20668541. The next prime is 20668553. The reversal of 20668551 is 15586602.

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

It is not a de Polignac number, because 20668551 - 2⁵ = 20668519 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20668553) 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, 83896 + ... + 84141.

It is an arithmetic number, because the mean of its divisors is an integer number (3528798).

Almost surely, 2^20668551 is an apocalyptic number.

20668551 is a deficient number, since it is larger than the sum of its proper divisors (7561833).

20668551 is a wasteful number, since it uses less digits than its factorization.

20668551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168081.

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 20668551 is about 4546.2678099734. The cubic root of 20668551 is about 274.4332172202.

The spelling of 20668551 in words is "twenty million, six hundred sixty-eight thousand, five hundred fifty-one".