21001107986 has 8 divisors (see below), whose sum is σ = 32269995324. Its totient is φ = 10244442880.

The previous prime is 21001107971. The next prime is 21001107989. The reversal of 21001107986 is 68970110012.

It can be written as a sum of positive squares in 2 ways, for example, as 20229657361 + 771450625 = 142231^2 + 27775^2 .

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 (21001107989) 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, 128055455 + ... + 128055618.

Almost surely, 2^21001107986 is an apocalyptic number.

21001107986 is a deficient number, since it is larger than the sum of its proper divisors (11268887338).

21001107986 is a wasteful number, since it uses less digits than its factorization.

21001107986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256111116.

The product of its (nonzero) digits is 6048, while the sum is 35.

Adding to 21001107986 its reverse (68970110012), we get a palindrome (89971217998).

The spelling of 21001107986 in words is "twenty-one billion, one million, one hundred seven thousand, nine hundred eighty-six".