21531142221 has 8 divisors (see below), whose sum is σ = 28709184000. Its totient is φ = 14353597632.

The previous prime is 21531142219. The next prime is 21531142229. The reversal of 21531142221 is 12224113512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21531142221 - 2¹ = 21531142219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21531142191 and 21531142200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531142229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7596 + ... + 207653.

It is an arithmetic number, because the mean of its divisors is an integer number (3588648000).

Almost surely, 2^21531142221 is an apocalyptic number.

It is an amenable number.

21531142221 is a deficient number, since it is larger than the sum of its proper divisors (7178041779).

21531142221 is a wasteful number, since it uses less digits than its factorization.

21531142221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248595.

The product of its digits is 960, while the sum is 24.

Adding to 21531142221 its reverse (12224113512), we get a palindrome (33755255733).

The spelling of 21531142221 in words is "twenty-one billion, five hundred thirty-one million, one hundred forty-two thousand, two hundred twenty-one".