21011221111021 has 8 divisors (see below), whose sum is σ = 21108421807200. Its totient is φ = 20914061119248.

The previous prime is 21011221111009. The next prime is 21011221111037. The reversal of 21011221111021 is 12011112211012.

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-21011221111021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011221110986 and 21011221111004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011221111081) 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, 9141091 + ... + 11206336.

It is an arithmetic number, because the mean of its divisors is an integer number (2638552725900).

Almost surely, 2^{21011221111021} is an apocalyptic number.

It is an amenable number.

21011221111021 is a deficient number, since it is larger than the sum of its proper divisors (97200696179).

21011221111021 is a wasteful number, since it uses less digits than its factorization.

21011221111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20352203.

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

Adding to 21011221111021 its reverse (12011112211012), we get a palindrome (33022333322033).

The spelling of 21011221111021 in words is "twenty-one trillion, eleven billion, two hundred twenty-one million, one hundred eleven thousand, twenty-one".