639283217 has 2 divisors, whose sum is σ = 639283218. Its totient is φ = 639283216.

The previous prime is 639283213. The next prime is 639283273. The reversal of 639283217 is 712382936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 414163201 + 225120016 = 20351^2 + 15004^2 .

It is a cyclic number.

It is not a de Polignac number, because 639283217 - 2² = 639283213 is a prime.

It is not a weakly prime, because it can be changed into another prime (639283213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319641608 + 319641609.

It is an arithmetic number, because the mean of its divisors is an integer number (319641609).

Almost surely, 2^639283217 is an apocalyptic number.

It is an amenable number.

639283217 is a deficient number, since it is larger than the sum of its proper divisors (1).

639283217 is an equidigital number, since it uses as much as digits as its factorization.

639283217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 41.

The square root of 639283217 is about 25284.0506446258. The cubic root of 639283217 is about 861.4520345481.

The spelling of 639283217 in words is "six hundred thirty-nine million, two hundred eighty-three thousand, two hundred seventeen".