21404042011 has 4 divisors (see below), whose sum is σ = 23349864024. Its totient is φ = 19458220000.

The previous prime is 21404041993. The next prime is 21404042047. The reversal of 21404042011 is 11024040412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21404042011 - 2⁹ = 21404041499 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21404042011.

It is not an unprimeable number, because it can be changed into a prime (21404042071) 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, 972910990 + ... + 972911011.

It is an arithmetic number, because the mean of its divisors is an integer number (5837466006).

Almost surely, 2^21404042011 is an apocalyptic number.

21404042011 is a deficient number, since it is larger than the sum of its proper divisors (1945822013).

21404042011 is a wasteful number, since it uses less digits than its factorization.

21404042011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945822012.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21404042011 its reverse (11024040412), we get a palindrome (32428082423).

The spelling of 21404042011 in words is "twenty-one billion, four hundred four million, forty-two thousand, eleven".