21042011 has 8 divisors (see below), whose sum is σ = 21967344. Its totient is φ = 20135520.

The previous prime is 21041989. The next prime is 21042013. The reversal of 21042011 is 11024012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042011 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21041983 and 21042001.

It is not an unprimeable number, because it can be changed into a prime (21042013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2405 + ... + 6918.

It is an arithmetic number, because the mean of its divisors is an integer number (2745918).

Almost surely, 2^21042011 is an apocalyptic number.

21042011 is a deficient number, since it is larger than the sum of its proper divisors (925333).

21042011 is an equidigital number, since it uses as much as digits as its factorization.

21042011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9421.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21042011 is about 4587.1571806512. The cubic root of 21042011 is about 276.0762715413.

Adding to 21042011 its reverse (11024012), we get a palindrome (32066023).

The spelling of 21042011 in words is "twenty-one million, forty-two thousand, eleven".