21111021011 has 16 divisors (see below), whose sum is σ = 22902633600. Its totient is φ = 19394157888.

The previous prime is 21111020977. The next prime is 21111021013. The reversal of 21111021011 is 11012011112.

It is not a de Polignac number, because 21111021011 - 2¹⁰ = 21111019987 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111020983 and 21111021001.

It is not an unprimeable number, because it can be changed into a prime (21111021013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20615 + ... + 206511.

It is an arithmetic number, because the mean of its divisors is an integer number (1431414600).

Almost surely, 2^21111021011 is an apocalyptic number.

21111021011 is a deficient number, since it is larger than the sum of its proper divisors (1791612589).

21111021011 is a wasteful number, since it uses less digits than its factorization.

21111021011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186098.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111021011 its reverse (11012011112), we get a palindrome (32123032123).

The spelling of 21111021011 in words is "twenty-one billion, one hundred eleven million, twenty-one thousand, eleven".