21002009986 has 16 divisors (see below), whose sum is σ = 32412333240. Its totient is φ = 10200136320.

The previous prime is 21002009957. The next prime is 21002010023. The reversal of 21002009986 is 68990020012.

It can be written as a sum of positive squares in 4 ways, for example, as 10645080625 + 10356929361 = 103175^2 + 101769^2 .

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 540441 + ... + 577996.

Almost surely, 2^21002009986 is an apocalyptic number.

21002009986 is a deficient number, since it is larger than the sum of its proper divisors (11410323254).

21002009986 is a wasteful number, since it uses less digits than its factorization.

21002009986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1118709.

The product of its (nonzero) digits is 15552, while the sum is 37.

Adding to 21002009986 its reverse (68990020012), we get a palindrome (89992029998).

The spelling of 21002009986 in words is "twenty-one billion, two million, nine thousand, nine hundred eighty-six".