21020100111 has 24 divisors (see below), whose sum is σ = 30878722784. Its totient is φ = 13776998400.

The previous prime is 21020100071. The next prime is 21020100119. The reversal of 21020100111 is 11100102012.

It is a happy number.

It is not a de Polignac number, because 21020100111 - 2²⁷ = 20885882383 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020100093 and 21020100102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020100119) 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 23 ways as a sum of consecutive naturals, for example, 52095 + ... + 211551.

Almost surely, 2^21020100111 is an apocalyptic number.

21020100111 is a deficient number, since it is larger than the sum of its proper divisors (9858622673).

21020100111 is a wasteful number, since it uses less digits than its factorization.

21020100111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159711 (or 159708 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21020100111 its reverse (11100102012), we get a palindrome (32120202123).

The spelling of 21020100111 in words is "twenty-one billion, twenty million, one hundred thousand, one hundred eleven".