21211212100021 has 8 divisors (see below), whose sum is σ = 21813399576864. Its totient is φ = 20616505213200.

The previous prime is 21211212100019. The next prime is 21211212100049. The reversal of 21211212100021 is 12000121211212.

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

It is not a de Polignac number, because 21211212100021 - 2¹ = 21211212100019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211212099968 and 21211212100004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211212100721) 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, 1870141755 + ... + 1870153096.

It is an arithmetic number, because the mean of its divisors is an integer number (2726674947108).

Almost surely, 2^{21211212100021} is an apocalyptic number.

It is an amenable number.

21211212100021 is a deficient number, since it is larger than the sum of its proper divisors (602187476843).

21211212100021 is a wasteful number, since it uses less digits than its factorization.

21211212100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3740295011.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21211212100021 its reverse (12000121211212), we get a palindrome (33211333311233).

The spelling of 21211212100021 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, one hundred thousand, twenty-one".