21203120111 has 16 divisors (see below), whose sum is σ = 21813176448. Its totient is φ = 20597702400.

The previous prime is 21203120089. The next prime is 21203120119. The reversal of 21203120111 is 11102130212.

It is a cyclic number.

It is not a de Polignac number, because 21203120111 - 2³⁴ = 4023250927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203120119) 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, 17952941 + ... + 17954121.

It is an arithmetic number, because the mean of its divisors is an integer number (1363323528).

Almost surely, 2^21203120111 is an apocalyptic number.

21203120111 is a deficient number, since it is larger than the sum of its proper divisors (610056337).

21203120111 is a wasteful number, since it uses less digits than its factorization.

21203120111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21203120111 its reverse (11102130212), we get a palindrome (32305250323).

The spelling of 21203120111 in words is "twenty-one billion, two hundred three million, one hundred twenty thousand, one hundred eleven".