21002011121 has 16 divisors (see below), whose sum is σ = 25886886144. Its totient is φ = 16592382144.

The previous prime is 21002011073. The next prime is 21002011127. The reversal of 21002011121 is 12111020012.

It is not a de Polignac number, because 21002011121 - 2³⁴ = 3822141937 is a prime.

It is a super-2 number, since 2×21002011121² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002011127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108845 + ... + 232058.

It is an arithmetic number, because the mean of its divisors is an integer number (1617930384).

Almost surely, 2^21002011121 is an apocalyptic number.

It is an amenable number.

21002011121 is a deficient number, since it is larger than the sum of its proper divisors (4884875023).

21002011121 is a wasteful number, since it uses less digits than its factorization.

21002011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341600.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21002011121 its reverse (12111020012), we get a palindrome (33113031133).

The spelling of 21002011121 in words is "twenty-one billion, two million, eleven thousand, one hundred twenty-one".