20910009 has 8 divisors (see below), whose sum is σ = 27945280. Its totient is φ = 13907376.

The previous prime is 20909989. The next prime is 20910011. The reversal of 20910009 is 90001902.

It is a happy number.

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

It is not a de Polignac number, because 20910009 - 2⁸ = 20909753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20910509) 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, 6622 + ... + 9255.

It is an arithmetic number, because the mean of its divisors is an integer number (3493160).

Almost surely, 2^20910009 is an apocalyptic number.

It is an amenable number.

20910009 is a deficient number, since it is larger than the sum of its proper divisors (7035271).

20910009 is a wasteful number, since it uses less digits than its factorization.

20910009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16319.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 20910009 is about 4572.7463301609. The cubic root of 20910009 is about 275.4977607489.

The spelling of 20910009 in words is "twenty million, nine hundred ten thousand, nine".