21253393 has 8 divisors (see below), whose sum is σ = 24701760. Its totient is φ = 17908080.

The previous prime is 21253373. The next prime is 21253423. The reversal of 21253393 is 39335212.

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 21253393 - 2⁵ = 21253361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21253313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25318 + ... + 26143.

It is an arithmetic number, because the mean of its divisors is an integer number (3087720).

Almost surely, 2^21253393 is an apocalyptic number.

It is an amenable number.

21253393 is a deficient number, since it is larger than the sum of its proper divisors (3448367).

21253393 is an equidigital number, since it uses as much as digits as its factorization.

21253393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51527.

The product of its digits is 4860, while the sum is 28.

The square root of 21253393 is about 4610.1402364787. The cubic root of 21253393 is about 276.9976540614.

The spelling of 21253393 in words is "twenty-one million, two hundred fifty-three thousand, three hundred ninety-three".