21100121122013 has 4 divisors (see below), whose sum is σ = 21100350760188. Its totient is φ = 21099891483840.

The previous prime is 21100121121997. The next prime is 21100121122037. The reversal of 21100121122013 is 31022112100112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11734550378329 + 9365570743684 = 3425573^2 + 3060322^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100121122013 - 2⁴ = 21100121121997 is a prime.

It is a super-2 number, since 2×21100121122013² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100121121982 and 21100121122000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100121122063) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114681206 + ... + 114865047.

It is an arithmetic number, because the mean of its divisors is an integer number (5275087690047).

Almost surely, 2^{21100121122013} is an apocalyptic number.

It is an amenable number.

21100121122013 is a deficient number, since it is larger than the sum of its proper divisors (229638175).

21100121122013 is an equidigital number, since it uses as much as digits as its factorization.

21100121122013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229638174.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21100121122013 its reverse (31022112100112), we get a palindrome (52122233222125).

The spelling of 21100121122013 in words is "twenty-one trillion, one hundred billion, one hundred twenty-one million, one hundred twenty-two thousand, thirteen".