21002120002121 has 4 divisors (see below), whose sum is σ = 21255157592592. Its totient is φ = 20749082411652.

The previous prime is 21002120002117. The next prime is 21002120002159. The reversal of 21002120002121 is 12120002120012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21002120002121 - 2² = 21002120002117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002120002096 and 21002120002105.

It is not an unprimeable number, because it can be changed into a prime (21002120002021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126518795111 + ... + 126518795276.

It is an arithmetic number, because the mean of its divisors is an integer number (5313789398148).

Almost surely, 2^{21002120002121} is an apocalyptic number.

It is an amenable number.

21002120002121 is a deficient number, since it is larger than the sum of its proper divisors (253037590471).

21002120002121 is an equidigital number, since it uses as much as digits as its factorization.

21002120002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253037590470.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21002120002121 its reverse (12120002120012), we get a palindrome (33122122122133).

The spelling of 21002120002121 in words is "twenty-one trillion, two billion, one hundred twenty million, two thousand, one hundred twenty-one".