21010105 has 8 divisors (see below), whose sum is σ = 26539200. Its totient is φ = 15923376.

The previous prime is 21010097. The next prime is 21010111. The reversal of 21010105 is 50101012.

It is a happy number.

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 21010105 - 2³ = 21010097 is a prime.

It is a super-2 number, since 2×21010105² = 882849024222050, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21010091 and 21010100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110485 + ... + 110674.

It is an arithmetic number, because the mean of its divisors is an integer number (3317400).

Almost surely, 2^21010105 is an apocalyptic number.

It is an amenable number.

21010105 is a deficient number, since it is larger than the sum of its proper divisors (5529095).

21010105 is a wasteful number, since it uses less digits than its factorization.

21010105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221183.

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

The square root of 21010105 is about 4583.6781082445. The cubic root of 21010105 is about 275.9366628100.

Adding to 21010105 its reverse (50101012), we get a palindrome (71111117).

It can be divided in two parts, 21010 and 105, that multiplied together give a triangular number (2206050 = T₂₁₀₀).

The spelling of 21010105 in words is "twenty-one million, ten thousand, one hundred five".