21144144011 has 4 divisors (see below), whose sum is σ = 21145475592. Its totient is φ = 21142812432.

The previous prime is 21144144001. The next prime is 21144144017. The reversal of 21144144011 is 11044144112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21144144011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144144017) 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, 641681 + ... + 673826.

It is an arithmetic number, because the mean of its divisors is an integer number (5286368898).

Almost surely, 2^21144144011 is an apocalyptic number.

21144144011 is a deficient number, since it is larger than the sum of its proper divisors (1331581).

21144144011 is a wasteful number, since it uses less digits than its factorization.

21144144011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331580.

The product of its (nonzero) digits is 512, while the sum is 23.

Adding to 21144144011 its reverse (11044144112), we get a palindrome (32188288123).

The spelling of 21144144011 in words is "twenty-one billion, one hundred forty-four million, one hundred forty-four thousand, eleven".