21050111 has 2 divisors, whose sum is σ = 21050112. Its totient is φ = 21050110.

The previous prime is 21050101. The next prime is 21050137. The reversal of 21050111 is 11105012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21050111 - 2²² = 16855807 is a prime.

It is a super-2 number, since 2×21050111² = 886214346224642, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21050092 and 21050101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21050101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525055 + 10525056.

It is an arithmetic number, because the mean of its divisors is an integer number (10525056).

Almost surely, 2^21050111 is an apocalyptic number.

21050111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050111 is an equidigital number, since it uses as much as digits as its factorization.

21050111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10, while the sum is 11.

The square root of 21050111 is about 4588.0399954665. The cubic root of 21050111 is about 276.1116916495. Note that the first 3 decimals are identical.

Adding to 21050111 its reverse (11105012), we get a palindrome (32155123).

It can be divided in two parts, 2105011 and 1, that added together give a palindrome (2105012).

The spelling of 21050111 in words is "twenty-one million, fifty thousand, one hundred eleven".