21321402606 has 32 divisors (see below), whose sum is σ = 54149594880. Its totient is φ = 6091829208.

The previous prime is 21321402593. The next prime is 21321402607. The reversal of 21321402606 is 60620412312.

21321402606 is a `hidden beast` number, since 2 + 13 + 2 + 1 + 40 + 2 + 606 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21321402606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321402607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28202536 + ... + 28203291.

It is an arithmetic number, because the mean of its divisors is an integer number (1692174840).

Almost surely, 2^21321402606 is an apocalyptic number.

21321402606 is an abundant number, since it is smaller than the sum of its proper divisors (32828192274).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21321402606 is a wasteful number, since it uses less digits than its factorization.

21321402606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56405845 (or 56405839 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

Adding to 21321402606 its reverse (60620412312), we get a palindrome (81941814918).

The spelling of 21321402606 in words is "twenty-one billion, three hundred twenty-one million, four hundred two thousand, six hundred six".