417640021 has 2 divisors, whose sum is σ = 417640022. Its totient is φ = 417640020.

The previous prime is 417640001. The next prime is 417640031. The reversal of 417640021 is 120046714.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 388641796 + 28998225 = 19714^2 + 5385^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-417640021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (417640001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 208820010 + 208820011.

It is an arithmetic number, because the mean of its divisors is an integer number (208820011).

Almost surely, 2^417640021 is an apocalyptic number.

It is an amenable number.

417640021 is a deficient number, since it is larger than the sum of its proper divisors (1).

417640021 is an equidigital number, since it uses as much as digits as its factorization.

417640021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 417640021 is about 20436.2428298354. The cubic root of 417640021 is about 747.4819380952.

Adding to 417640021 its reverse (120046714), we get a palindrome (537686735).

The spelling of 417640021 in words is "four hundred seventeen million, six hundred forty thousand, twenty-one".