21101021011 has 16 divisors (see below), whose sum is σ = 24293841408. Its totient is φ = 17952984000.

The previous prime is 21101020991. The next prime is 21101021023. The reversal of 21101021011 is 11012010112.

It is not a de Polignac number, because 21101021011 - 2¹¹ = 21101018963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101022011) 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, 1507716 + ... + 1521646.

It is an arithmetic number, because the mean of its divisors is an integer number (1518365088).

Almost surely, 2^21101021011 is an apocalyptic number.

21101021011 is a deficient number, since it is larger than the sum of its proper divisors (3192820397).

21101021011 is a wasteful number, since it uses less digits than its factorization.

21101021011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15522.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21101021011 its reverse (11012010112), we get a palindrome (32113031123).

The spelling of 21101021011 in words is "twenty-one billion, one hundred one million, twenty-one thousand, eleven".