21740217 has 8 divisors (see below), whose sum is σ = 29462400. Its totient is φ = 14255760.

The previous prime is 21740197. The next prime is 21740219. The reversal of 21740217 is 71204712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21740217 - 2¹⁸ = 21478073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21740219) 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, 59217 + ... + 59582.

It is an arithmetic number, because the mean of its divisors is an integer number (3682800).

Almost surely, 2^21740217 is an apocalyptic number.

It is an amenable number.

21740217 is a deficient number, since it is larger than the sum of its proper divisors (7722183).

21740217 is a wasteful number, since it uses less digits than its factorization.

21740217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118863.

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 21740217 is about 4662.6405608839. The cubic root of 21740217 is about 279.0966507812.

Adding to 21740217 its reverse (71204712), we get a palindrome (92944929).

The spelling of 21740217 in words is "twenty-one million, seven hundred forty thousand, two hundred seventeen".