21245393 has 16 divisors (see below), whose sum is σ = 24385536. Its totient is φ = 18336000.

The previous prime is 21245387. The next prime is 21245407. The reversal of 21245393 is 39354212.

It is a cyclic number.

It is not a de Polignac number, because 21245393 - 2¹⁰ = 21244369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21245303) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 55280 + ... + 55662.

It is an arithmetic number, because the mean of its divisors is an integer number (1524096).

Almost surely, 2^21245393 is an apocalyptic number.

It is an amenable number.

21245393 is a deficient number, since it is larger than the sum of its proper divisors (3140143).

21245393 is a wasteful number, since it uses less digits than its factorization.

21245393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664.

The product of its digits is 6480, while the sum is 29.

The square root of 21245393 is about 4609.2725022502. The cubic root of 21245393 is about 276.9628947592.

The spelling of 21245393 in words is "twenty-one million, two hundred forty-five thousand, three hundred ninety-three".