21112245666 has 12 divisors (see below), whose sum is σ = 45743198982. Its totient is φ = 7037415216.

The previous prime is 21112245653. The next prime is 21112245667. The reversal of 21112245666 is 66654221112.

It can be written as a sum of positive squares in only one way, i.e., 10864935225 + 10247310441 = 104235^2 + 101229^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21112245666.

It is not an unprimeable number, because it can be changed into a prime (21112245667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 586451251 + ... + 586451286.

Almost surely, 2^21112245666 is an apocalyptic number.

21112245666 is an abundant number, since it is smaller than the sum of its proper divisors (24630953316).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21112245666 is a wasteful number, since it uses less digits than its factorization.

21112245666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172902545 (or 1172902542 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

Adding to 21112245666 its reverse (66654221112), we get a palindrome (87766466778).

The spelling of 21112245666 in words is "twenty-one billion, one hundred twelve million, two hundred forty-five thousand, six hundred sixty-six".