21180617 has 2 divisors, whose sum is σ = 21180618. Its totient is φ = 21180616.

The previous prime is 21180583. The next prime is 21180659. The reversal of 21180617 is 71608112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18139081 + 3041536 = 4259^2 + 1744^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21180617 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21180667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10590308 + 10590309.

It is an arithmetic number, because the mean of its divisors is an integer number (10590309).

Almost surely, 2^21180617 is an apocalyptic number.

It is an amenable number.

21180617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21180617 is an equidigital number, since it uses as much as digits as its factorization.

21180617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 21180617 is about 4602.2404326589. The cubic root of 21180617 is about 276.6811268067.

Adding to 21180617 its reverse (71608112), we get a palindrome (92788729).

The spelling of 21180617 in words is "twenty-one million, one hundred eighty thousand, six hundred seventeen".