21212001221021 has 8 divisors (see below), whose sum is σ = 22843731346464. Its totient is φ = 19580276484720.

The previous prime is 21212001221003. The next prime is 21212001221029. The reversal of 21212001221021 is 12012210021212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212001221021 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 (21212001221029) 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, 11058506 + ... + 12834116.

It is an arithmetic number, because the mean of its divisors is an integer number (2855466418308).

Almost surely, 2^{21212001221021} is an apocalyptic number.

It is an amenable number.

21212001221021 is a deficient number, since it is larger than the sum of its proper divisors (1631730125443).

21212001221021 is a wasteful number, since it uses less digits than its factorization.

21212001221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2694571.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21212001221021 its reverse (12012210021212), we get a palindrome (33224211242233).

The spelling of 21212001221021 in words is "twenty-one trillion, two hundred twelve billion, one million, two hundred twenty-one thousand, twenty-one".