20668109 has 16 divisors (see below), whose sum is σ = 26320896. Its totient is φ = 15759600.

The previous prime is 20668091. The next prime is 20668111. The reversal of 20668109 is 90186602.

20668109 = T₁₇₇ + T₁₇₈ + ... + T₅₀₅.

It is a cyclic number.

It is not a de Polignac number, because 20668109 - 2¹² = 20664013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20668139) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 764 + ... + 6474.

It is an arithmetic number, because the mean of its divisors is an integer number (1645056).

Almost surely, 2^20668109 is an apocalyptic number.

It is an amenable number.

20668109 is a deficient number, since it is larger than the sum of its proper divisors (5652787).

20668109 is a wasteful number, since it uses less digits than its factorization.

20668109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5776.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20668109 is about 4546.2191984109. The cubic root of 20668109 is about 274.4312609414.

The spelling of 20668109 in words is "twenty million, six hundred sixty-eight thousand, one hundred nine".