20111211 has 6 divisors (see below), whose sum is σ = 29049540. Its totient is φ = 13407468.

The previous prime is 20111183. The next prime is 20111213. The reversal of 20111211 is 11211102.

It is a happy number.

It is not a de Polignac number, because 20111211 - 2⁷ = 20111083 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2234579 = 20111211 / (2 + 0 + 1 + 1 + 1 + 2 + 1 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 20111193 and 20111202.

It is not an unprimeable number, because it can be changed into a prime (20111213) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1117281 + ... + 1117298.

It is an arithmetic number, because the mean of its divisors is an integer number (4841590).

Almost surely, 2^20111211 is an apocalyptic number.

20111211 is a deficient number, since it is larger than the sum of its proper divisors (8938329).

20111211 is a wasteful number, since it uses less digits than its factorization.

20111211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2234585 (or 2234582 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 20111211 is about 4484.5524860347. The cubic root of 20111211 is about 271.9439538142.

Adding to 20111211 its reverse (11211102), we get a palindrome (31322313).

The spelling of 20111211 in words is "twenty million, one hundred eleven thousand, two hundred eleven".