21002120206 has 8 divisors (see below), whose sum is σ = 31539942720. Its totient is φ = 10488805968.

The previous prime is 21002120197. The next prime is 21002120213. The reversal of 21002120206 is 60202120012.

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 21002120206.

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, 6124926 + ... + 6128353.

It is an arithmetic number, because the mean of its divisors is an integer number (3942492840).

Almost surely, 2^21002120206 is an apocalyptic number.

21002120206 is a deficient number, since it is larger than the sum of its proper divisors (10537822514).

21002120206 is a wasteful number, since it uses less digits than its factorization.

21002120206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12254138.

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

Adding to 21002120206 its reverse (60202120012), we get a palindrome (81204240218).

The spelling of 21002120206 in words is "twenty-one billion, two million, one hundred twenty thousand, two hundred six".