21020000021021 has 16 divisors (see below), whose sum is σ = 21337892978688. Its totient is φ = 20704323385200.

The previous prime is 21020000020997. The next prime is 21020000021029. The reversal of 21020000021021 is 12012000002012.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21020000021021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020000020993 and 21020000021011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020000021029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166114586 + ... + 166241076.

It is an arithmetic number, because the mean of its divisors is an integer number (1333618311168).

Almost surely, 2^{21020000021021} is an apocalyptic number.

It is an amenable number.

21020000021021 is a deficient number, since it is larger than the sum of its proper divisors (317892957667).

21020000021021 is a wasteful number, since it uses less digits than its factorization.

21020000021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135232.

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

Adding to 21020000021021 its reverse (12012000002012), we get a palindrome (33032000023033).

The spelling of 21020000021021 in words is "twenty-one trillion, twenty billion, twenty-one thousand, twenty-one".