21663387106 has 8 divisors (see below), whose sum is σ = 32534663004. Its totient is φ = 10818499440.

The previous prime is 21663387103. The next prime is 21663387107. The reversal of 21663387106 is 60178336612.

It can be written as a sum of positive squares in 2 ways, for example, as 18932384025 + 2731003081 = 137595^2 + 52259^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21663387103) 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 3 ways as a sum of consecutive naturals, for example, 6595005 + ... + 6598288.

Almost surely, 2^21663387106 is an apocalyptic number.

21663387106 is a deficient number, since it is larger than the sum of its proper divisors (10871275898).

21663387106 is a wasteful number, since it uses less digits than its factorization.

21663387106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13194116.

The product of its (nonzero) digits is 217728, while the sum is 43.

The spelling of 21663387106 in words is "twenty-one billion, six hundred sixty-three million, three hundred eighty-seven thousand, one hundred six".