21000121000051 has 2 divisors, whose sum is σ = 21000121000052. Its totient is φ = 21000121000050.

The previous prime is 21000121000031. The next prime is 21000121000063. The reversal of 21000121000051 is 15000012100012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000121000051 - 2¹³ = 21000120991859 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000120999995 and 21000121000040.

It is not a weakly prime, because it can be changed into another prime (21000121000031) 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 as a sum of consecutive naturals, namely, 10500060500025 + 10500060500026.

It is an arithmetic number, because the mean of its divisors is an integer number (10500060500026).

Almost surely, 2^{21000121000051} is an apocalyptic number.

21000121000051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000121000051 is an equidigital number, since it uses as much as digits as its factorization.

21000121000051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20, while the sum is 13.

Adding to 21000121000051 its reverse (15000012100012), we get a palindrome (36000133100063).

The spelling of 21000121000051 in words is "twenty-one trillion, one hundred twenty-one million, fifty-one", and thus it is an aban number.