21497105 has 16 divisors (see below), whose sum is σ = 30434304. Its totient is φ = 14264640.

The previous prime is 21497101. The next prime is 21497123. The reversal of 21497105 is 50179412.

It is not a de Polignac number, because 21497105 - 2² = 21497101 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21497101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8822 + ... + 10991.

It is an arithmetic number, because the mean of its divisors is an integer number (1902144).

Almost surely, 2^21497105 is an apocalyptic number.

It is an amenable number.

21497105 is a deficient number, since it is larger than the sum of its proper divisors (8937199).

21497105 is a wasteful number, since it uses less digits than its factorization.

21497105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19856.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21497105 is about 4636.4970613600. The cubic root of 21497105 is about 278.0524071790.

The spelling of 21497105 in words is "twenty-one million, four hundred ninety-seven thousand, one hundred five".