21112011 has 24 divisors (see below), whose sum is σ = 33050160. Its totient is φ = 12934656.

The previous prime is 21112009. The next prime is 21112019. The reversal of 21112011 is 11021112.

It is a happy number.

It is not a de Polignac number, because 21112011 - 2¹ = 21112009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21111984 and 21112002.

It is not an unprimeable number, because it can be changed into a prime (21112019) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4975 + ... + 8183.

It is an arithmetic number, because the mean of its divisors is an integer number (1377090).

Almost surely, 2^21112011 is an apocalyptic number.

21112011 is a deficient number, since it is larger than the sum of its proper divisors (11938149).

21112011 is a wasteful number, since it uses less digits than its factorization.

21112011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3275 (or 3272 counting only the distinct ones).

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

The square root of 21112011 is about 4594.7808435224. The cubic root of 21112011 is about 276.3820716666.

Adding to 21112011 its reverse (11021112), we get a palindrome (32133123).

The spelling of 21112011 in words is "twenty-one million, one hundred twelve thousand, eleven".