21748315 has 4 divisors (see below), whose sum is σ = 26097984. Its totient is φ = 17398648.

The previous prime is 21748313. The next prime is 21748333. The reversal of 21748315 is 51384712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21748315 - 2¹ = 21748313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21748313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2174827 + ... + 2174836.

It is an arithmetic number, because the mean of its divisors is an integer number (6524496).

Almost surely, 2^21748315 is an apocalyptic number.

21748315 is a deficient number, since it is larger than the sum of its proper divisors (4349669).

21748315 is an equidigital number, since it uses as much as digits as its factorization.

21748315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4349668.

The product of its digits is 6720, while the sum is 31.

The square root of 21748315 is about 4663.5088720833. The cubic root of 21748315 is about 279.1312999924.

The spelling of 21748315 in words is "twenty-one million, seven hundred forty-eight thousand, three hundred fifteen".