21152325421221 has 16 divisors (see below), whose sum is σ = 28629931065600. Its totient is φ = 13889007894528.

The previous prime is 21152325421189. The next prime is 21152325421247. The reversal of 21152325421221 is 12212452325112.

It is a happy number.

It is not a de Polignac number, because 21152325421221 - 2⁵ = 21152325421189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152325421321) 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, 109011036 + ... + 109204901.

It is an arithmetic number, because the mean of its divisors is an integer number (1789370691600).

Almost surely, 2^{21152325421221} is an apocalyptic number.

It is an amenable number.

21152325421221 is a deficient number, since it is larger than the sum of its proper divisors (7477605644379).

21152325421221 is a wasteful number, since it uses less digits than its factorization.

21152325421221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218216428.

The product of its digits is 19200, while the sum is 33.

Adding to 21152325421221 its reverse (12212452325112), we get a palindrome (33364777746333).

The spelling of 21152325421221 in words is "twenty-one trillion, one hundred fifty-two billion, three hundred twenty-five million, four hundred twenty-one thousand, two hundred twenty-one".