21621302006 has 4 divisors (see below), whose sum is σ = 32431953012. Its totient is φ = 10810651002.

The previous prime is 21621301979. The next prime is 21621302009. The reversal of 21621302006 is 60020312612.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621302009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5405325500 + ... + 5405325503.

It is an arithmetic number, because the mean of its divisors is an integer number (8107988253).

Almost surely, 2^21621302006 is an apocalyptic number.

21621302006 is a deficient number, since it is larger than the sum of its proper divisors (10810651006).

21621302006 is a wasteful number, since it uses less digits than its factorization.

21621302006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10810651005.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21621302006 its reverse (60020312612), we get a palindrome (81641614618).

The spelling of 21621302006 in words is "twenty-one billion, six hundred twenty-one million, three hundred two thousand, six".