20111309 has 4 divisors (see below), whose sum is σ = 20231904. Its totient is φ = 19990716.

The previous prime is 20111303. The next prime is 20111317. The reversal of 20111309 is 90311102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20111309 - 2⁴ = 20111293 is a prime.

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 (20111303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60047 + ... + 60380.

It is an arithmetic number, because the mean of its divisors is an integer number (5057976).

Almost surely, 2^20111309 is an apocalyptic number.

It is an amenable number.

20111309 is a deficient number, since it is larger than the sum of its proper divisors (120595).

20111309 is a wasteful number, since it uses less digits than its factorization.

20111309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120594.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 20111309 is about 4484.5634124182. The cubic root of 20111309 is about 271.9443955324.

The spelling of 20111309 in words is "twenty million, one hundred eleven thousand, three hundred nine".