21101220000021 has 16 divisors (see below), whose sum is σ = 33552250435584. Its totient is φ = 11533586086704.

The previous prime is 21101219999989. The next prime is 21101220000071. The reversal of 21101220000021 is 12000002210112.

It is not a de Polignac number, because 21101220000021 - 2⁵ = 21101219999989 is a prime.

It is a super-2 number, since 2×21101220000021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21101219999961 and 21101220000006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101220000071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21843912561 + ... + 21843913526.

It is an arithmetic number, because the mean of its divisors is an integer number (2097015652224).

Almost surely, 2^{21101220000021} is an apocalyptic number.

21101220000021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21101220000021 is a deficient number, since it is larger than the sum of its proper divisors (12451030435563).

21101220000021 is a wasteful number, since it uses less digits than its factorization.

21101220000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43687826120.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21101220000021 its reverse (12000002210112), we get a palindrome (33101222210133).

The spelling of 21101220000021 in words is "twenty-one trillion, one hundred one billion, two hundred twenty million, twenty-one", and thus it is an aban number.