21019105 has 8 divisors (see below), whose sum is σ = 25759872. Its totient is φ = 16457328.

The previous prime is 21019069. The next prime is 21019127. The reversal of 21019105 is 50191012.

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 21019105 - 2²¹ = 18921953 is a prime.

It is a Duffinian number.

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, 44487 + ... + 44956.

It is an arithmetic number, because the mean of its divisors is an integer number (3219984).

Almost surely, 2^21019105 is an apocalyptic number.

It is an amenable number.

21019105 is a deficient number, since it is larger than the sum of its proper divisors (4740767).

21019105 is an equidigital number, since it uses as much as digits as its factorization.

21019105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89495.

The product of its (nonzero) digits is 90, while the sum is 19.

The square root of 21019105 is about 4584.6597474622. The cubic root of 21019105 is about 275.9760577495.

The spelling of 21019105 in words is "twenty-one million, nineteen thousand, one hundred five".