21222016420666 has 16 divisors (see below), whose sum is σ = 33705998983656. Its totient is φ = 9986699851776.

The previous prime is 21222016420663. The next prime is 21222016420697. The reversal of 21222016420666 is 66602461022212.

It can be written as a sum of positive squares in 4 ways, for example, as 20360210548441 + 861805872225 = 4512229^2 + 928335^2 .

It is not an unprimeable number, because it can be changed into a prime (21222016420663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1459671 + ... + 6676426.

Almost surely, 2^{21222016420666} is an apocalyptic number.

21222016420666 is a deficient number, since it is larger than the sum of its proper divisors (12483982562990).

21222016420666 is a wasteful number, since it uses less digits than its factorization.

21222016420666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8212833.

The product of its (nonzero) digits is 165888, while the sum is 40.

Adding to 21222016420666 its reverse (66602461022212), we get a palindrome (87824477442878).

The spelling of 21222016420666 in words is "twenty-one trillion, two hundred twenty-two billion, sixteen million, four hundred twenty thousand, six hundred sixty-six".