2001022010021 has 2 divisors, whose sum is σ = 2001022010022. Its totient is φ = 2001022010020.

The previous prime is 2001022010017. The next prime is 2001022010023. The reversal of 2001022010021 is 1200102201002.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1864901596996 + 136120413025 = 1365614^2 + 368945^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001022010021 - 2² = 2001022010017 is a prime.

Together with 2001022010023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 2001022009984 and 2001022010011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001022010023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000511005010 + 1000511005011.

It is an arithmetic number, because the mean of its divisors is an integer number (1000511005011).

Almost surely, 2^{2001022010021} is an apocalyptic number.

It is an amenable number.

2001022010021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001022010021 is an equidigital number, since it uses as much as digits as its factorization.

2001022010021 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 2001022010021 its reverse (1200102201002), we get a palindrome (3201124211023).

The spelling of 2001022010021 in words is "two trillion, one billion, twenty-two million, ten thousand, twenty-one".