21002021206 has 8 divisors (see below), whose sum is σ = 31503941280. Its totient is φ = 10500707448.

The previous prime is 21002021197. The next prime is 21002021219. The reversal of 21002021206 is 60212020012.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21002021206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51861 + ... + 211408.

It is an arithmetic number, because the mean of its divisors is an integer number (3937992660).

Almost surely, 2^21002021206 is an apocalyptic number.

21002021206 is a deficient number, since it is larger than the sum of its proper divisors (10501920074).

21002021206 is a wasteful number, since it uses less digits than its factorization.

21002021206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303158.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21002021206 its reverse (60212020012), we get a palindrome (81214041218).

The spelling of 21002021206 in words is "twenty-one billion, two million, twenty-one thousand, two hundred six".