21123331012121 has 16 divisors (see below), whose sum is σ = 23158188522000. Its totient is φ = 19149983643648.

The previous prime is 21123331012099. The next prime is 21123331012123. The reversal of 21123331012121 is 12121013332112.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 6634802307721 + 14488528704400 = 2575811^2 + 3806380^2 .

It is not a de Polignac number, because 21123331012121 - 2⁶ = 21123331012057 is a prime.

It is a super-2 number, since 2×21123331012121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123331012123) 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, 61092656 + ... + 61437441.

It is an arithmetic number, because the mean of its divisors is an integer number (1447386782625).

Almost surely, 2^{21123331012121} is an apocalyptic number.

It is an amenable number.

21123331012121 is a deficient number, since it is larger than the sum of its proper divisors (2034857509879).

21123331012121 is a wasteful number, since it uses less digits than its factorization.

21123331012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122530348.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 21123331012121 its reverse (12121013332112), we get a palindrome (33244344344233).

The spelling of 21123331012121 in words is "twenty-one trillion, one hundred twenty-three billion, three hundred thirty-one million, twelve thousand, one hundred twenty-one".