21144071 has 4 divisors (see below), whose sum is σ = 22770552. Its totient is φ = 19517592.

The previous prime is 21144059. The next prime is 21144083. The reversal of 21144071 is 17044112.

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

It is an interprime number because it is at equal distance from previous prime (21144059) and next prime (21144083).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21144071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143071) 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, 813221 + ... + 813246.

It is an arithmetic number, because the mean of its divisors is an integer number (5692638).

Almost surely, 2^21144071 is an apocalyptic number.

21144071 is a deficient number, since it is larger than the sum of its proper divisors (1626481).

21144071 is a wasteful number, since it uses less digits than its factorization.

21144071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626480.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 21144071 is about 4598.2682609870. The cubic root of 21144071 is about 276.5219024601.

Adding to 21144071 its reverse (17044112), we get a palindrome (38188183).

The spelling of 21144071 in words is "twenty-one million, one hundred forty-four thousand, seventy-one".