646953397 has 2 divisors, whose sum is σ = 646953398. Its totient is φ = 646953396.

The previous prime is 646953383. The next prime is 646953409. The reversal of 646953397 is 793359646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 437688241 + 209265156 = 20921^2 + 14466^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646953397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646993397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323476698 + 323476699.

It is an arithmetic number, because the mean of its divisors is an integer number (323476699).

Almost surely, 2^646953397 is an apocalyptic number.

It is an amenable number.

646953397 is a deficient number, since it is larger than the sum of its proper divisors (1).

646953397 is an equidigital number, since it uses as much as digits as its factorization.

646953397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3674160, while the sum is 52.

The square root of 646953397 is about 25435.2785909650. The cubic root of 646953397 is about 864.8836075809.

The spelling of 646953397 in words is "six hundred forty-six million, nine hundred fifty-three thousand, three hundred ninety-seven".