21011031011 has 32 divisors (see below), whose sum is σ = 22731432192. Its totient is φ = 19385533440.

The previous prime is 21011031007. The next prime is 21011031023. The reversal of 21011031011 is 11013011012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21011031011 - 2² = 21011031007 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011030983 and 21011031001.

It is not an unprimeable number, because it can be changed into a prime (21011031911) 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 31 ways as a sum of consecutive naturals, for example, 11193005 + ... + 11194881.

It is an arithmetic number, because the mean of its divisors is an integer number (710357256).

Almost surely, 2^21011031011 is an apocalyptic number.

21011031011 is a deficient number, since it is larger than the sum of its proper divisors (1720401181).

21011031011 is a wasteful number, since it uses less digits than its factorization.

21011031011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2159.

The product of its (nonzero) digits is 6, while the sum is 11.

Adding to 21011031011 its reverse (11013011012), we get a palindrome (32024042023).

The spelling of 21011031011 in words is "twenty-one billion, eleven million, thirty-one thousand, eleven".