221421651706 has 12 divisors (see below), whose sum is σ = 343192042746. Its totient is φ = 107139507960.

The previous prime is 221421651589. The next prime is 221421651707. The reversal of 221421651706 is 607156124122.

It can be written as a sum of positive squares in only one way, i.e., 139284957681 + 82136694025 = 373209^2 + 286595^2 .

It is not an unprimeable number, because it can be changed into a prime (221421651707) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 57599965 + ... + 57603808.

Almost surely, 2^221421651706 is an apocalyptic number.

221421651706 is a deficient number, since it is larger than the sum of its proper divisors (121770391040).

221421651706 is a wasteful number, since it uses less digits than its factorization.

221421651706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115203837 (or 115203806 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

Adding to 221421651706 its reverse (607156124122), we get a palindrome (828577775828).

The spelling of 221421651706 in words is "two hundred twenty-one billion, four hundred twenty-one million, six hundred fifty-one thousand, seven hundred six".