21111220011 has 16 divisors (see below), whose sum is σ = 32195692800. Its totient is φ = 12053723808.

The previous prime is 21111220001. The next prime is 21111220037. The reversal of 21111220011 is 11002211112.

It is not a de Polignac number, because 21111220011 - 2¹⁵ = 21111187243 is a prime.

It is a super-2 number, since 2×21111220011² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21111220001) 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 15 ways as a sum of consecutive naturals, for example, 383181 + ... + 434798.

It is an arithmetic number, because the mean of its divisors is an integer number (2012230800).

Almost surely, 2^21111220011 is an apocalyptic number.

21111220011 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21111220011 is a deficient number, since it is larger than the sum of its proper divisors (11084472789).

21111220011 is a wasteful number, since it uses less digits than its factorization.

21111220011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819218.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111220011 its reverse (11002211112), we get a palindrome (32113431123).

The spelling of 21111220011 in words is "twenty-one billion, one hundred eleven million, two hundred twenty thousand, eleven".