21340017 has 28 divisors (see below), whose sum is σ = 32514564. Its totient is φ = 13996800.

The previous prime is 21340003. The next prime is 21340019. The reversal of 21340017 is 71004312.

It can be written as a sum of positive squares in 2 ways, for example, as 17969121 + 3370896 = 4239^2 + 1836^2 .

It is not a de Polignac number, because 21340017 - 2⁷ = 21339889 is a prime.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21340019) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 53017 + ... + 53417.

Almost surely, 2^21340017 is an apocalyptic number.

21340017 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21340017 is a deficient number, since it is larger than the sum of its proper divisors (11174547).

21340017 is an frugal number, since it uses more digits than its factorization.

21340017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21340017 is about 4619.5256249966. The cubic root of 21340017 is about 277.3734704388.

Adding to 21340017 its reverse (71004312), we get a palindrome (92344329).

The spelling of 21340017 in words is "twenty-one million, three hundred forty thousand, seventeen".