21748219 has 4 divisors (see below), whose sum is σ = 23027544. Its totient is φ = 20468896.

The previous prime is 21748201. The next prime is 21748261. The reversal of 21748219 is 91284712.

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 21748219 - 2⁷ = 21748091 is a prime.

It is a super-2 number, since 2×21748219² = 945970059343922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21740219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 639637 + ... + 639670.

It is an arithmetic number, because the mean of its divisors is an integer number (5756886).

Almost surely, 2^21748219 is an apocalyptic number.

21748219 is a deficient number, since it is larger than the sum of its proper divisors (1279325).

21748219 is a wasteful number, since it uses less digits than its factorization.

21748219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279324.

The product of its digits is 8064, while the sum is 34.

The square root of 21748219 is about 4663.4985793929. The cubic root of 21748219 is about 279.1308892840.

The spelling of 21748219 in words is "twenty-one million, seven hundred forty-eight thousand, two hundred nineteen".