20659887 has 8 divisors (see below), whose sum is σ = 30607280. Its totient is φ = 13773240.

The previous prime is 20659871. The next prime is 20659889. The reversal of 20659887 is 78895602.

It is not a de Polignac number, because 20659887 - 2⁴ = 20659871 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 (20659889) 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 in 7 ways as a sum of consecutive naturals, for example, 382564 + ... + 382617.

It is an arithmetic number, because the mean of its divisors is an integer number (3825910).

Almost surely, 2^20659887 is an apocalyptic number.

20659887 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

20659887 is a deficient number, since it is larger than the sum of its proper divisors (9947393).

20659887 is an equidigital number, since it uses as much as digits as its factorization.

20659887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765190 (or 765184 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 20659887 is about 4545.3148405804. The cubic root of 20659887 is about 274.3948655282.

The spelling of 20659887 in words is "twenty million, six hundred fifty-nine thousand, eight hundred eighty-seven".