20900909 has 8 divisors (see below), whose sum is σ = 21928320. Its totient is φ = 19894000.

The previous prime is 20900903. The next prime is 20900911. The reversal of 20900909 is 90900902.

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

It is not a de Polignac number, because 20900909 - 2⁸ = 20900653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20900903) 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, 3017 + ... + 7134.

It is an arithmetic number, because the mean of its divisors is an integer number (2741040).

Almost surely, 2^20900909 is an apocalyptic number.

20900909 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20900909 is a deficient number, since it is larger than the sum of its proper divisors (1027411).

20900909 is a wasteful number, since it uses less digits than its factorization.

20900909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10251.

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 20900909 is about 4571.7511962048. The cubic root of 20900909 is about 275.4577895658.

The spelling of 20900909 in words is "twenty million, nine hundred thousand, nine hundred nine".