21311422666 has 8 divisors (see below), whose sum is σ = 33847553700. Its totient is φ = 10028904768.

The previous prime is 21311422663. The next prime is 21311422667. The reversal of 21311422666 is 66622411312.

It can be written as a sum of positive squares in 2 ways, for example, as 16506853441 + 4804569225 = 128479^2 + 69315^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (34), and also a Moran number because the ratio is a prime number: 626806549 = 21311422666 / (2 + 1 + 3 + 1 + 1 + 4 + 2 + 2 + 6 + 6 + 6).

It is not an unprimeable number, because it can be changed into a prime (21311422661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 313403241 + ... + 313403308.

Almost surely, 2^21311422666 is an apocalyptic number.

21311422666 is a deficient number, since it is larger than the sum of its proper divisors (12536131034).

21311422666 is a wasteful number, since it uses less digits than its factorization.

21311422666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626806568.

The product of its digits is 20736, while the sum is 34.

Adding to 21311422666 its reverse (66622411312), we get a palindrome (87933833978).

The spelling of 21311422666 in words is "twenty-one billion, three hundred eleven million, four hundred twenty-two thousand, six hundred sixty-six".