21044477 has 2 divisors, whose sum is σ = 21044478.
Its totient is φ = 21044476.
The previous prime is 21044473. The next prime is 21044479. The reversal of 21044477 is 77444012.
Adding to 21044477 its reverse (77444012), we get a palindrome (98488489).
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 11930116 + 9114361 = 3454^2 + 3019^2
It is a cyclic number.
It is not a de Polignac number, because 21044477 - 22 = 21044473 is a prime.
Together with 21044479, 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 (21044473) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522238 + 10522239.
It is an arithmetic number, because the mean of its divisors is an integer number (10522239).
Almost surely, 221044477 is an apocalyptic number.
It is an amenable number.
21044477 is a deficient number, since it is larger than the sum of its proper divisors (1).
21044477 is an equidigital number, since it uses as much as digits as its factorization.
21044477 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 6272, while the sum is 29.
The square root of 21044477 is about 4587.4259667051.
The cubic root of 21044477 is about 276.0870559588.
The spelling of 21044477 in words is "twenty-one million, forty-four thousand, four hundred seventy-seven".