21001011226121 has 2 divisors, whose sum is σ = 21001011226122. Its totient is φ = 21001011226120.

The previous prime is 21001011226081. The next prime is 21001011226133. The reversal of 21001011226121 is 12162211010012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20361708636025 + 639302590096 = 4512395^2 + 799564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001011226121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001011226093 and 21001011226102.

It is not a weakly prime, because it can be changed into another prime (21001011226171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500505613060 + 10500505613061.

It is an arithmetic number, because the mean of its divisors is an integer number (10500505613061).

Almost surely, 2^{21001011226121} is an apocalyptic number.

It is an amenable number.

21001011226121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001011226121 is an equidigital number, since it uses as much as digits as its factorization.

21001011226121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 20.

Adding to 21001011226121 its reverse (12162211010012), we get a palindrome (33163222236133).

The spelling of 21001011226121 in words is "twenty-one trillion, one billion, eleven million, two hundred twenty-six thousand, one hundred twenty-one".