21123121134131 has 2 divisors, whose sum is σ = 21123121134132. Its totient is φ = 21123121134130.

The previous prime is 21123121134113. The next prime is 21123121134179. The reversal of 21123121134131 is 13143112132112.

Together with previous prime (21123121134113) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123121134131 is a prime.

It is a super-2 number, since 2×21123121134131² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21123121134131.

It is not a weakly prime, because it can be changed into another prime (21123120134131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561560567065 + 10561560567066.

It is an arithmetic number, because the mean of its divisors is an integer number (10561560567066).

Almost surely, 2^{21123121134131} is an apocalyptic number.

21123121134131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123121134131 is an equidigital number, since it uses as much as digits as its factorization.

21123121134131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

Adding to 21123121134131 its reverse (13143112132112), we get a palindrome (34266233266243).

The spelling of 21123121134131 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred twenty-one million, one hundred thirty-four thousand, one hundred thirty-one".