20842909 has 8 divisors (see below), whose sum is σ = 21640320. Its totient is φ = 20050800.

The previous prime is 20842891. The next prime is 20842919. The reversal of 20842909 is 90924802.

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

It is a cyclic number.

It is not a de Polignac number, because 20842909 - 2⁹ = 20842397 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 (20842919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7864 + ... + 10174.

It is an arithmetic number, because the mean of its divisors is an integer number (2705040).

Almost surely, 2^20842909 is an apocalyptic number.

20842909 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20842909 is a deficient number, since it is larger than the sum of its proper divisors (797411).

20842909 is a wasteful number, since it uses less digits than its factorization.

20842909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2651.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 20842909 is about 4565.4034870973. The cubic root of 20842909 is about 275.2027551568.

The spelling of 20842909 in words is "twenty million, eight hundred forty-two thousand, nine hundred nine".