21297105 has 24 divisors (see below), whose sum is σ = 37034088. Its totient is φ = 11321856.

The previous prime is 21297071. The next prime is 21297109. The reversal of 21297105 is 50179212.

It can be written as a sum of positive squares in 4 ways, for example, as 3732624 + 17564481 = 1932^2 + 4191^2 .

It is not a de Polignac number, because 21297105 - 2⁶ = 21297041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21297109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18939 + ... + 20031.

It is an arithmetic number, because the mean of its divisors is an integer number (1543087).

Almost surely, 2^21297105 is an apocalyptic number.

It is an amenable number.

21297105 is a deficient number, since it is larger than the sum of its proper divisors (15736983).

21297105 is a wasteful number, since it uses less digits than its factorization.

21297105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537 (or 1534 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21297105 is about 4614.8786549594. The cubic root of 21297105 is about 277.1874250150.

The spelling of 21297105 in words is "twenty-one million, two hundred ninety-seven thousand, one hundred five".