21121002011 has 4 divisors (see below), whose sum is σ = 22363413912. Its totient is φ = 19878590112.

The previous prime is 21121001969. The next prime is 21121002029. The reversal of 21121002011 is 11020012112.

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

It is a cyclic number.

It is not a de Polignac number, because 21121002011 - 2⁶ = 21121001947 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21121001983 and 21121002001.

It is not an unprimeable number, because it can be changed into a prime (21121002211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 621205925 + ... + 621205958.

It is an arithmetic number, because the mean of its divisors is an integer number (5590853478).

Almost surely, 2^21121002011 is an apocalyptic number.

21121002011 is a deficient number, since it is larger than the sum of its proper divisors (1242411901).

21121002011 is a wasteful number, since it uses less digits than its factorization.

21121002011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242411900.

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

Adding to 21121002011 its reverse (11020012112), we get a palindrome (32141014123).

The spelling of 21121002011 in words is "twenty-one billion, one hundred twenty-one million, two thousand, eleven".