647339909 has 2 divisors, whose sum is σ = 647339910. Its totient is φ = 647339908.

The previous prime is 647339897. The next prime is 647339921. The reversal of 647339909 is 909933746.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (647339897) and next prime (647339921).

It can be written as a sum of positive squares in only one way, i.e., 342139009 + 305200900 = 18497^2 + 17470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647339909 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647339009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323669954 + 323669955.

It is an arithmetic number, because the mean of its divisors is an integer number (323669955).

Almost surely, 2^647339909 is an apocalyptic number.

It is an amenable number.

647339909 is a deficient number, since it is larger than the sum of its proper divisors (1).

647339909 is an equidigital number, since it uses as much as digits as its factorization.

647339909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1102248, while the sum is 50.

The square root of 647339909 is about 25442.8754074692. The cubic root of 647339909 is about 865.0558102696.

The spelling of 647339909 in words is "six hundred forty-seven million, three hundred thirty-nine thousand, nine hundred nine".