21021031330121 has 4 divisors (see below), whose sum is σ = 22257562584852. Its totient is φ = 19784500075392.

The previous prime is 21021031330073. The next prime is 21021031330139. The reversal of 21021031330121 is 12103313012012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10347873009721 + 10673158320400 = 3216811^2 + 3266980^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021031330121 - 2¹⁸ = 21021031067977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021031330093 and 21021031330102.

It is not an unprimeable number, because it can be changed into a prime (21021031330181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 618265627340 + ... + 618265627373.

It is an arithmetic number, because the mean of its divisors is an integer number (5564390646213).

Almost surely, 2^{21021031330121} is an apocalyptic number.

It is an amenable number.

21021031330121 is a deficient number, since it is larger than the sum of its proper divisors (1236531254731).

21021031330121 is a wasteful number, since it uses less digits than its factorization.

21021031330121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236531254730.

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 21021031330121 its reverse (12103313012012), we get a palindrome (33124344342133).

The spelling of 21021031330121 in words is "twenty-one trillion, twenty-one billion, thirty-one million, three hundred thirty thousand, one hundred twenty-one".