21413218221 has 6 divisors (see below), whose sum is σ = 30930204110. Its totient is φ = 14275478808.

The previous prime is 21413218193. The next prime is 21413218279. The reversal of 21413218221 is 12281231412.

It is a happy number.

21413218221 is a `hidden beast` number, since 2 + 1 + 413 + 21 + 8 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14006722500 + 7406495721 = 118350^2 + 86061^2 .

It is not a de Polignac number, because 21413218221 - 2¹¹ = 21413216173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21413618221) 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, 1189623226 + ... + 1189623243.

Almost surely, 2^21413218221 is an apocalyptic number.

It is an amenable number.

21413218221 is a deficient number, since it is larger than the sum of its proper divisors (9516985889).

21413218221 is a wasteful number, since it uses less digits than its factorization.

21413218221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2379246475 (or 2379246472 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

Adding to 21413218221 its reverse (12281231412), we get a palindrome (33694449633).

The spelling of 21413218221 in words is "twenty-one billion, four hundred thirteen million, two hundred eighteen thousand, two hundred twenty-one".