21000011011221 has 8 divisors (see below), whose sum is σ = 30545470561824. Its totient is φ = 12727279400720.

The previous prime is 21000011011163. The next prime is 21000011011237. The reversal of 21000011011221 is 12211011000012.

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 21000011011221 - 2⁹ = 21000011010709 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21000011011197 and 21000011011206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000018011221) 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, 318181984986 + ... + 318181985051.

It is an arithmetic number, because the mean of its divisors is an integer number (3818183820228).

Almost surely, 2^{21000011011221} is an apocalyptic number.

It is an amenable number.

21000011011221 is a deficient number, since it is larger than the sum of its proper divisors (9545459550603).

21000011011221 is a wasteful number, since it uses less digits than its factorization.

21000011011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636363970051.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21000011011221 its reverse (12211011000012), we get a palindrome (33211022011233).

The spelling of 21000011011221 in words is "twenty-one trillion, eleven million, eleven thousand, two hundred twenty-one".