21001105 has 16 divisors (see below), whose sum is σ = 26210304. Its totient is φ = 16136640.

The previous prime is 21001087. The next prime is 21001117. The reversal of 21001105 is 50110012.

It is a happy number.

It is not a de Polignac number, because 21001105 - 2⁷ = 21000977 is a prime.

It is a super-2 number, since 2×21001105² = 882092822442050, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001091 and 21001100.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23904 + ... + 24766.

It is an arithmetic number, because the mean of its divisors is an integer number (1638144).

Almost surely, 2^21001105 is an apocalyptic number.

It is an amenable number.

21001105 is a deficient number, since it is larger than the sum of its proper divisors (5209199).

21001105 is a wasteful number, since it uses less digits than its factorization.

21001105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1056.

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

The square root of 21001105 is about 4582.6962587542. The cubic root of 21001105 is about 275.8972566187.

Adding to 21001105 its reverse (50110012), we get a palindrome (71111117).

The spelling of 21001105 in words is "twenty-one million, one thousand, one hundred five".