21000001111 has 8 divisors (see below), whose sum is σ = 22239146160. Its totient is φ = 19761283968.

The previous prime is 21000001091. The next prime is 21000001153. The reversal of 21000001111 is 11110000012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21000001111 - 2³³ = 12410066519 is a prime.

It is a Duffinian number.

21000001111 is a modest number, since divided by 1111 gives 210 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21000001094 and 21000001103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000001411) 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 7 ways as a sum of consecutive naturals, for example, 3036 + ... + 204961.

It is an arithmetic number, because the mean of its divisors is an integer number (2779893270).

Almost surely, 2^21000001111 is an apocalyptic number.

21000001111 is a deficient number, since it is larger than the sum of its proper divisors (1239145049).

21000001111 is a wasteful number, since it uses less digits than its factorization.

21000001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213953.

The product of its (nonzero) digits is 2, while the sum is 7.

Adding to 21000001111 its reverse (11110000012), we get a palindrome (32110001123).

The spelling of 21000001111 in words is "twenty-one billion, one thousand, one hundred eleven".