21000121000031 has 2 divisors, whose sum is σ = 21000121000032. Its totient is φ = 21000121000030.

The previous prime is 21000120999973. The next prime is 21000121000051. The reversal of 21000121000031 is 13000012100012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000121000031 - 2²² = 21000116805727 is a prime.

It is a super-2 number, since 2×21000121000031² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21000120999976 and 21000121000021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000121000051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500060500015 + 10500060500016.

It is an arithmetic number, because the mean of its divisors is an integer number (10500060500016).

Almost surely, 2^{21000121000031} is an apocalyptic number.

21000121000031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000121000031 is an equidigital number, since it uses as much as digits as its factorization.

21000121000031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21000121000031 its reverse (13000012100012), we get a palindrome (34000133100043).

The spelling of 21000121000031 in words is "twenty-one trillion, one hundred twenty-one million, thirty-one", and thus it is an aban number.