21740017 has 16 divisors (see below), whose sum is σ = 24131520. Its totient is φ = 19461312.

The previous prime is 21740011. The next prime is 21740023. The reversal of 21740017 is 71004712.

It is an interprime number because it is at equal distance from previous prime (21740011) and next prime (21740023).

It is a de Polignac number, because none of the positive numbers 2^k-21740017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21740017.

It is not an unprimeable number, because it can be changed into a prime (21740011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95658 + ... + 95884.

It is an arithmetic number, because the mean of its divisors is an integer number (1508220).

Almost surely, 2^21740017 is an apocalyptic number.

It is an amenable number.

21740017 is a deficient number, since it is larger than the sum of its proper divisors (2391503).

21740017 is a wasteful number, since it uses less digits than its factorization.

21740017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432.

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 21740017 is about 4662.6191137600. The cubic root of 21740017 is about 279.0957949249.

Adding to 21740017 its reverse (71004712), we get a palindrome (92744729).

The spelling of 21740017 in words is "twenty-one million, seven hundred forty thousand, seventeen".