21144411437 has 2 divisors, whose sum is σ = 21144411438. Its totient is φ = 21144411436.

The previous prime is 21144411401. The next prime is 21144411439. The reversal of 21144411437 is 73411444112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17268850921 + 3875560516 = 131411^2 + 62254^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144411437 - 2¹² = 21144407341 is a prime.

It is a super-2 number, since 2×21144411437² (a number of 21 digits) contains 22 as substring.

Together with 21144411439, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21144411439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572205718 + 10572205719.

It is an arithmetic number, because the mean of its divisors is an integer number (10572205719).

Almost surely, 2^21144411437 is an apocalyptic number.

It is an amenable number.

21144411437 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144411437 is an equidigital number, since it uses as much as digits as its factorization.

21144411437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 32.

Adding to 21144411437 its reverse (73411444112), we get a palindrome (94555855549).

The spelling of 21144411437 in words is "twenty-one billion, one hundred forty-four million, four hundred eleven thousand, four hundred thirty-seven".