21016441 has 2 divisors, whose sum is σ = 21016442. Its totient is φ = 21016440.

The previous prime is 21016439. The next prime is 21016459. The reversal of 21016441 is 14461012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19316025 + 1700416 = 4395^2 + 1304^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016441 - 2¹ = 21016439 is a prime.

Together with 21016439, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21016241) 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, 10508220 + 10508221.

It is an arithmetic number, because the mean of its divisors is an integer number (10508221).

Almost surely, 2^21016441 is an apocalyptic number.

It is an amenable number.

21016441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21016441 is an equidigital number, since it uses as much as digits as its factorization.

21016441 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21016441 is about 4584.3692041545. The cubic root of 21016441 is about 275.9643980193.

Adding to 21016441 its reverse (14461012), we get a palindrome (35477453).

The spelling of 21016441 in words is "twenty-one million, sixteen thousand, four hundred forty-one".