21213543320021 has 32 divisors (see below), whose sum is σ = 24395026981248. Its totient is φ = 18273288683520.

The previous prime is 21213543319963. The next prime is 21213543320107. The reversal of 21213543320021 is 12002334531212.

It is a de Polignac number, because none of the positive numbers 2^k-21213543320021 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 (21213543322021) 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, 33062750 + ... + 33698256.

It is an arithmetic number, because the mean of its divisors is an integer number (762344593164).

Almost surely, 2^{21213543320021} is an apocalyptic number.

It is an amenable number.

21213543320021 is a deficient number, since it is larger than the sum of its proper divisors (3181483661227).

21213543320021 is a wasteful number, since it uses less digits than its factorization.

21213543320021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636821.

The product of its (nonzero) digits is 8640, while the sum is 29.

Adding to 21213543320021 its reverse (12002334531212), we get a palindrome (33215877851233).

The spelling of 21213543320021 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred twenty thousand, twenty-one".