21221406463121 has 8 divisors (see below), whose sum is σ = 21233428886184. Its totient is φ = 21209386826880.

The previous prime is 21221406463031. The next prime is 21221406463133. The reversal of 21221406463121 is 12136460412212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 839468250625 + 20381938212496 = 916225^2 + 4514636^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21221406463121 - 2¹⁰ = 21221406462097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221406463421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14632811 + ... + 16017551.

It is an arithmetic number, because the mean of its divisors is an integer number (2654178610773).

Almost surely, 2^{21221406463121} is an apocalyptic number.

It is an amenable number.

21221406463121 is a deficient number, since it is larger than the sum of its proper divisors (12022423063).

21221406463121 is a wasteful number, since it uses less digits than its factorization.

21221406463121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1393411.

The product of its (nonzero) digits is 27648, while the sum is 35.

Adding to 21221406463121 its reverse (12136460412212), we get a palindrome (33357866875333).

The spelling of 21221406463121 in words is "twenty-one trillion, two hundred twenty-one billion, four hundred six million, four hundred sixty-three thousand, one hundred twenty-one".