21002121010111 has 16 divisors (see below), whose sum is σ = 21543241674240. Its totient is φ = 20465118192960.

The previous prime is 21002121010061. The next prime is 21002121010153. The reversal of 21002121010111 is 11101012120012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21002121010111 - 2⁷ = 21002121009983 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002121010091 and 21002121010100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002121050111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9138795 + ... + 11203651.

It is an arithmetic number, because the mean of its divisors is an integer number (1346452604640).

Almost surely, 2^{21002121010111} is an apocalyptic number.

21002121010111 is a deficient number, since it is larger than the sum of its proper divisors (541120664129).

21002121010111 is a wasteful number, since it uses less digits than its factorization.

21002121010111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2065854.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21002121010111 its reverse (11101012120012), we get a palindrome (32103133130123).

The spelling of 21002121010111 in words is "twenty-one trillion, two billion, one hundred twenty-one million, ten thousand, one hundred eleven".