20010122021 has 2 divisors, whose sum is σ = 20010122022. Its totient is φ = 20010122020.

The previous prime is 20010121997. The next prime is 20010122087. The reversal of 20010122021 is 12022101002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17360961121 + 2649160900 = 131761^2 + 51470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20010122021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20010121993 and 20010122011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20010122621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005061010 + 10005061011.

It is an arithmetic number, because the mean of its divisors is an integer number (10005061011).

Almost surely, 2^20010122021 is an apocalyptic number.

It is an amenable number.

20010122021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20010122021 is an equidigital number, since it uses as much as digits as its factorization.

20010122021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20010122021 its reverse (12022101002), we get a palindrome (32032223023).

The spelling of 20010122021 in words is "twenty billion, ten million, one hundred twenty-two thousand, twenty-one".