21740417 has 2 divisors, whose sum is σ = 21740418. Its totient is φ = 21740416.

The previous prime is 21740387. The next prime is 21740419. The reversal of 21740417 is 71404712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16128256 + 5612161 = 4016^2 + 2369^2 .

It is a cyclic number.

It is not a de Polignac number, because 21740417 - 2⁶ = 21740353 is a prime.

Together with 21740419, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21740419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10870208 + 10870209.

It is an arithmetic number, because the mean of its divisors is an integer number (10870209).

Almost surely, 2^21740417 is an apocalyptic number.

It is an amenable number.

21740417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21740417 is an equidigital number, since it uses as much as digits as its factorization.

21740417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1568, while the sum is 26.

The square root of 21740417 is about 4662.6620079092. The cubic root of 21740417 is about 279.0975066321.

The spelling of 21740417 in words is "twenty-one million, seven hundred forty thousand, four hundred seventeen".