21443422221 has 32 divisors (see below), whose sum is σ = 34313435520. Its totient is φ = 13156722432.

The previous prime is 21443422213. The next prime is 21443422229. The reversal of 21443422221 is 12222434412.

It is a happy number.

21443422221 is a `hidden beast` number, since 2 + 1 + 4 + 434 + 2 + 2 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (21443422213) and next prime (21443422229).

It is not a de Polignac number, because 21443422221 - 2³ = 21443422213 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443422229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27646 + ... + 208928.

It is an arithmetic number, because the mean of its divisors is an integer number (1072294860).

Almost surely, 2^21443422221 is an apocalyptic number.

It is an amenable number.

21443422221 is a deficient number, since it is larger than the sum of its proper divisors (12870013299).

21443422221 is a wasteful number, since it uses less digits than its factorization.

21443422221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181642 (or 181636 counting only the distinct ones).

The product of its digits is 6144, while the sum is 27.

Adding to 21443422221 its reverse (12222434412), we get a palindrome (33665856633).

The spelling of 21443422221 in words is "twenty-one billion, four hundred forty-three million, four hundred twenty-two thousand, two hundred twenty-one".