20735209 has 16 divisors (see below), whose sum is σ = 23224320. Its totient is φ = 18354960.

The previous prime is 20735201. The next prime is 20735293. The reversal of 20735209 is 90253702.

It is a cyclic number.

It is not a de Polignac number, because 20735209 - 2³ = 20735201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20735201) 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 15 ways as a sum of consecutive naturals, for example, 92872 + ... + 93094.

It is an arithmetic number, because the mean of its divisors is an integer number (1451520).

Almost surely, 2^20735209 is an apocalyptic number.

It is an amenable number.

20735209 is a deficient number, since it is larger than the sum of its proper divisors (2489111).

20735209 is a wasteful number, since it uses less digits than its factorization.

20735209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420.

The product of its (nonzero) digits is 3780, while the sum is 28.

The square root of 20735209 is about 4553.5929769798. The cubic root of 20735209 is about 274.7279248468.

The spelling of 20735209 in words is "twenty million, seven hundred thirty-five thousand, two hundred nine".