20406909 has 8 divisors (see below), whose sum is σ = 27257472. Its totient is φ = 13580480.

The previous prime is 20406833. The next prime is 20406917. The reversal of 20406909 is 90960402.

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 20406909 - 2⁷ = 20406781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20406989) 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, 3957 + ... + 7514.

It is an arithmetic number, because the mean of its divisors is an integer number (3407184).

Almost surely, 2^20406909 is an apocalyptic number.

It is an amenable number.

20406909 is a deficient number, since it is larger than the sum of its proper divisors (6850563).

20406909 is a wasteful number, since it uses less digits than its factorization.

20406909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12067.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 20406909 is about 4517.4006906627. The cubic root of 20406909 is about 273.2702847177.

The spelling of 20406909 in words is "twenty million, four hundred six thousand, nine hundred nine".